NRU :: Browsing by Author "Tweyongyere, Robert"

Browsing by Author "Tweyongyere, Robert"

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African animal trypanosomiasis as a constraint to livestock health and production in Karamoja region
(BMC Veterinary Research, 2017) Muhanguzi, Dennis; Mugenyi, Albert; Bigirwa, Godfrey; Kamusiime, Maureen; Kitibwa, Ann; Akurut, Grace Gloria; Ochwo, Sylvester; Amanyire, Wilson; Okech, Samuel George; Hattendorf, Jan; Tweyongyere, Robert
Background: Nagana (African Animal Trypanosomiasis-AAT) and tick-borne diseases (TBDs) constrain livestock production in most parts of sub-Saharan Africa. To this realization, Uganda government set up an African trypanosomiasis (AT) control unit, which among other activities generates national tsetse control priority maps using apparent tsetse density data. Such maps underestimate mechanically transmitted AAT and thus ought to be refined using actual AT prevalence data. W therefore set out to generate up-to-date cattle and donkey trypanosomiasis prevalence data as well as find out the constraints to livestock production in Karamoja region in a bid to re-define AT control priority in this region. Results: Livestock keepers and animal health workers indicated that TBDs and AAT were the most important livestock diseases in Karamoja region. The prevalence of Trypanosoma spp. in cattle and donkeys was 16.3% (95% CI: 12.4–21.1%) and 32.4% (95% CI; 20.2–47.6%) respectively. Trypanosoma vivax (12.1%) and Trypanosoma congolense savannah (29.6%) were the most prevalent Trypanosoma spp. in cattle and donkeys respectively. Majority of the cattle (85.7%) and more than half of the donkey (57.1%) herds were positive for Trypanosoma spp. Conclusions: African animal trypanosomiasis and TBDs are the most important constraints to livestock production in Karamoja region. In order to improve livestock production and hence Karamajong livelihoods, government of Uganda and her development partners will need to invest in livestock health programs particularly targeting tsetse and TBD control.
Carbapenem Resistance Profiles of Pathogenic Escherichia coli in Uganda
(2020) Ssekatawa, Kenneth; Byarugaba, Denis K.; Nakavuma, Jesca L.; Kato, Charles D.; Ejobi, Francis; Tweyongyere, Robert; Wampande, Eddie M.
Escherichia coli has been implicated as one of the main etiological agents of diarrhea, urinary tract infections, meningitis and septicemia worldwide. The ability to cause diseases is potentiated by presence of virulence factors. The virulence factors influence the capacity of E. coli to infect and colonize different body systems. Thus, pathogenic E. coli are grouped into DEC strains that are mainly clustered in phylogenetic group B1 and A; ExPEC belonging to A, B2 and D. Coexistence of virulence and beta-lactamase encoding genes complicates treatment outcomes. Therefore, this study aimed at presenting the CR profiles among pathogenic E. coli. Methods: This was a retrospective cross-sectional study involving use of archived E. coli clinical isolates collected in 2019 from four Ugandan tertiary hospitals. The isolates were subjected to antibiotics sensitivity assays to determine phenotypic resistance. Four sets of multiplex PCR were performed to detect CR genes, DEC pathotypes virulent genes, ExPEC PAI and the E. coli phylogenetic groups. Results: Antibiotic susceptibility revealed that all the 421 E. coli isolates used were MDR as they exhibited 100% resistance to more than one of the first-line antibiotics. The study registered phenotypic and genotypic CR prevalence of 22.8% and 33.0% respectively. The most predominant gene was blaOXA-48 with genotypic frequency of 33.0%, then blaVIM(21.0%), blaIMP(16.5%), blaKPC(14.8%) and blaNDM(14.8%). Spearman’s correlation revealed that presence of CR genes was highly associated with phenotypic resistance. Furthermore, of 421 MDR E. coli isolates, 19.7% harboured DEC virulent genes, where EPEC recorded significantly higher prevalence (10.8%) followed by S-ETEC(3.1%), STEC(2.9%), EIEC (2.0%) and L-ETEC(2.0%). Genetic analysis characterized 46.1% of the isolates as ExPEC and only PAI IV536(33.0%) and PAI IICFT073(13.1%) were detected. Phylogenetic group B2 was predominantly detected (41.1%), followed by A(30.2%), B1(21.6%), and D(7.1%). Furthermore, 38.6% and 23.1% of the DEC and ExPEC respectively expressed phenotypic resistance. Conclusion: Our results exhibited significant level of CR carriage among the MDR DEC and ExPEC clinical isolates belonging to phylogenetic groups B1 and B2 respectively. Virulence and CR genetic factors are mainly located on mobile elements. Thus, constitutes a great threat to the healthcare system as it promotes horizontal gene transfer.
Chemical tick control practices in southwestern and northwestern Uganda
(Ticks and tick-borne diseases, 2018) Vudriko, Patrick; Okwee-Acai, James; Byaruhanga, Joseph; Tayebwaa, Dickson S.; Okech, Samuel G.; Tweyongyere, Robert; Wampande, Eddie M.; Ademun Okurut, Anna R.; Mugabi, Kenneth; Muhindo, Jeanne B.; Nakavuma, Jesca L.; Umemiya-Shirafuji, Rika; Xuan, Xuenan
Tick acaricide failure is one of the leading challenges to cattle production in Uganda. To gain an understanding into the possible drivers of acaricide failure, this study characterized the current chemical tick control practices in the southwestern (Mbarara, Mitooma and Rukungiri districts) and northwestern (Adjumani district) regions of Uganda. A total of 85 farms participated in a survey that utilized a semi-structured questionnaire. Moreover, ticks were collected to determine the most common species on the farms. Tick acaricide failure was mainly encountered in the districts where 95% (60/63) of the farms reared exotic cattle (dairy cross-breeds) under a paddocking (fenced) system. In the northwestern region, local cattle were reared in communal grazing areas. All farms used chemical acaricides for tick control, predominantly amidine (amitraz) (48%, 41/85) and co-formulated organophosphates and pyrethroids (38%, 32/85). The spraying method was the most common (91%, 77/85) acaricide application technique, with cattle crush (81%, 69/85) as a common means of physical restraint. Less than optimal tick control practices encountered included use of substandard equipment for spraying, inappropriate dilutions, frequent interaction between animals in neighboring farms despite lack of synchronized chemical tick control and malpractices in acaricide rotation. Only Rhipicephalus appendiculatus and R. (Boophilus) decoloratus ticks were found in the southwestern region, where 51% (32/63) of the farmers used high acaricide concentrations above the manufacturers’ recommendation. Farmers in the northwestern region used 2.2 times less acaricide volume per cattle than those in the southwestern region, and more diverse tick species were encountered. Toxic effects of acaricide to cattle and workers were reported by 13% (11/85) and 32% (27/85) of the respondents, respectively. All 27 cases of human acaricide toxicity reported were from the southwestern region. Overall, our findings may inform strategies for more prudent chemical tick control and safe acaricide handling to benefit animal welfare, food safety and public health.
Effect of Praziquantel Treatment during Pregnancy on Cytokine Responses to Schistosome Antigens: Results of a Randomized, Placebo-Controlled Trial
(The Journal of infectious diseases, 2008) Tweyongyere, Robert; Mawa, Patrice A.; Ngom-wegi, Sophy; Ndibazza, Juliet; Duong, Trinh; Vennervald, Birgitte J.; Dunne, David W.; Katunguka-Rwakishaya, Eli; Elliott, Alison M.
Praziquantel treatment of schistosomiasis boosts antischistosome responses, with type 2 helper T cell bias that may contribute to immunologically mediated killing and to protection against reinfection. Praziquantel treatment during pregnancy was recommended in 2002, but the immunological effects of the treatment had not been investigated.A cohort of 387 Schistosoma mansoni-infected women were recruited from a larger trial of deworming during pregnancy. Women were randomized to receive either praziquantel or placebo during pregnancy. Six weeks after delivery, all women received praziquantel. Cytokine responses to S. mansoni worm and egg antigens were measured in whole blood culture before and 6 weeks after each treatment.Schistosome-specific cytokine responses were suppressed during pregnancy. Praziquantel treatment during pregnancy caused significant boosts in interferon-γ (IFN-γ), interleukin (IL)-2, IL-4, IL-5, IL-13, and IL-10 responses to schistosome worm antigen and in IFN-γ, IL-5, and IL-13 responses to schistosome egg antigen, but these boosts were not as substantial as those seen for women treated after delivery.Pregnancy suppresses a potentially beneficial boost in cytokine responses associated with praziquantel treatment. Further studies are needed on the long-term effects that treatment of schistosomiasis during pregnancy have on morbidity and resistance to reinfection among treated women and their offspring.
Effect of praziquantel treatment of Schistosoma mansoni during pregnancy on intensity of infection and antibody responses to schistosome antigens: results of a randomised, placebo-controlled trial
(BMC Infectious Diseases, 2009) Tweyongyere, Robert; Mawa, Patrice A.; Emojong, Nicholas O.; Mpairwe, Harriet; Jones, Frances M.; Duong, Trinh; Dunne, David W.; Vennervald, Birgitte J.; Katunguka-Rwakishaya, Eli; Elliott, Alison M.
Praziquantel treatment of schistosomiasis during pregnancy was only recommended in 2002; hence the effects of treatment during pregnancy are not fully known. We have therefore evaluated the effects on infection intensity and the immunological effects of praziquantel treatment against Schistosoma mansoni during pregnancy, compared with treatment after delivery.A nested cohort of 387 Schistosoma mansoni infected women was recruited within a larger trial of de-worming during pregnancy. Women were randomised to receive praziquantel or placebo during pregnancy. All women were treated after delivery. Infection intensity after treatment was assessed by a single Kato-Katz examination of stool samples with duplicate slides and categorised as undetected, light (1–99 eggs per gram (epg)), moderate (100–399 epg) or heavy (≥400 epg). Antibodies against S. mansoni worm and egg antigens were measured by ELISA. Results were compared between women first treated during pregnancy and women first treated after delivery.At enrolment, 252 (65.1%) of the women had light infection (median (IQR) epg: 35 (11, 59)), 75 (19.3%) moderate (median (IQR) epg: 179(131, 227)) and 60 (15.5%) had heavy infection (median (IQR) epg: 749 (521, 1169)) with S. mansoni. At six weeks after praziquantel treatment during pregnancy S. mansoni infection was not detectable in 81.9% of the women and prevalence and intensity had decreased to 11.8% light, 4.7% moderate and 1.6% heavy a similar reduction when compared with those first treated after delivery (undetected (88.5%), light (10.6%), moderate (0.9%) and heavy (0%), p = 0.16). Parasite specific antibody levels were lower during pregnancy than after delivery. Praziquantel treatment during pregnancy boosted anti-worm IgG isotypes and to a lesser extent IgE, but these boosts were less pronounced than in women whose treatment was delayed until after delivery. Praziquantel had limited effects on antibodies against egg antigens.S mansoni antigen-specific antibody levels and praziquantel-induced boosts in antibody levels were broadly suppressed during pregnancy, but this was not associated with major reduction in the efficacy of praziquantel. Long-term implications of these findings in relation to resistance to re-infection remain to be explored.
Effect of single-dose anthelmintic treatment during pregnancy on an infant’s response to immunisation and on susceptibility to infectious diseases in infancy: a randomised, double-blind, placebo-controlled trial
(The Lancet,, 2011) Webb, Emily L.; Mawa, Patrice A.; Ndibazza, Juliet; Kizito, Dennison; Namatovu, Alice; Kyosiimire-Lugemwa, Jacqueline; Nanteza, Bridget; Nampijja, Margaret; Muhangi, Lawrence; Woodburn, Patrick W; Akurut, Hellen; Mpairwe, Harriet; Akello, Miriam; Lyadda, Nancy; Bukusuba, Joseph; Kihembo, Macklyn; Kizza, Moses; Kizindo, Robert; Nabulime, Juliet; Ameke, Christine; Namujju, Proscovia B.; Tweyongyere, Robert; Muwanga, Moses; Whitworth, James A. G.; Elliott, Alison M.
Helminth infections affect the human immune response. We investigated whether prenatal exposure to and treatment of maternal helminth infections affects development of an infant's immune response to immunisations and unrelated infections.In this randomised, double-blind, placebo-controlled trial, we enrolled 2507 women in the second or third trimester of pregnancy who were planning to deliver in Entebbe General Hospital, Entebbe, Uganda. With a computer-generated random number sequence in blocks of 100, we assigned patients to 440 mg albendazole and 40 mg/kg praziquantel (n=628), 440 mg albendazole and a praziquantel-matching placebo (n=625), 40 mg/kg praziquantel and an albendazole-matching placebo (n=626), or an albendazole-matching placebo and praziquantel-matching placebo (n=628). All participants and hospital staff were masked to allocation. Primary outcomes were immune response at age 1 year to BCG, tetanus, and measles immunisation; incidence of infectious diseases during infancy; and vertical HIV transmission. Analysis was by intention-to-treat. This trial is registered, number ISRCTN32849447.Data were available at delivery for 2356 women, with 2345 livebirths; 2115 (90%) of liveborn infants remained in follow-up at 1 year of age. Neither albendazole nor praziquantel treatments affected infant response to BCG, tetanus, or measles immunisation. However, in infants of mothers with hookworm infection, albendazole treatment reduced interleukin-5 (geometric mean ratio 0·50, 95% CI 0·30–0·81, interaction p=0·02) and interleukin-13 (0·52, 0·34–0·82, 0·0005) response to tetanus toxoid. The rate per 100 person-years of malaria was 40·9 (95% CI 38·3–43·7), of diarrhoea was 134·1 (129·2–139·2), and of pneumonia was 22·3 (20·4–24·4). We noted no effect on infectious disease incidence for albendazole treatment (malaria [hazard ratio 0·95, 95% CI 0·79–1.14], diarrhoea [1·06, 0·96–1·16], pneumonia [1·11, 0·90–1·38]) or praziquantel treatment (malaria [1·00, 0·84–1·20], diarrhoea [1·07, 0·98–1·18], pneumonia [1·00, 0·80–1·24]). In HIV-exposed infants, 39 (18%) were infected at 6 weeks; vertical transmission was not associated with albendazole (odds ratio 0·70, 95% CI 0·35–1·42) or praziquantel (0·60, 0·29–1·23) treatment.These results do not accord with the recently advocated policy of routine antenatal anthelmintic treatment, and the value of such a policy may need to be reviewed.
Effect of single-dose anthelmintic treatment during pregnancy on an infant’s response to immunization and on susceptibility to infectious diseases in infancy: a randomized, double-blind, placebo-controlled trial
(The Lancet, 2011) Webb, Emily L; Mawa, Patrice A; Ndibazza, Juliet; Kizito, Dennison; Namatovu, Alice; Kyosiimire-Lugemwa, Jacqueline; Nanteza, Bridget; Nampijja, Margaret; Muhangi, Lawrence; Woodburn, Patrick W; Akurut, Hellen; Mpairwe, Harriet; Akello, Miriam; Lyadda, Nancy; Bukusuba, Joseph; Kihembo, Macklyn; Kizza, Moses; Kizindo, Robert; Nabulime, Juliet; Ameke, Christine; Namujju, Proscovia B; Tweyongyere, Robert; Muwanga, Moses; Whitworth, James A G; Elliott, Alison M
Helminth infections aff ect the human immune response. We investigated whether prenatal exposure to and treatment of maternal helminth infections aff ects development of an infant’s immune response to immunisations and unrelated infections. Methods In this randomised, double-blind, placebo-controlled trial, we enrolled 2507 women in the second or third trimester of pregnancy who were planning to deliver in Entebbe General Hospital, Entebbe, Uganda. With a computergenerated random number sequence in blocks of 100, we assigned patients to 440 mg albendazole and 40 mg/kg praziquantel (n=628), 440 mg albendazole and a praziquantel-matching placebo (n=625), 40 mg/kg praziquantel and an albendazole-matching placebo (n=626), or an albendazole-matching placebo and praziquantel-matching placebo (n=628). All participants and hospital staff were masked to allocation. Primary outcomes were immune response at age 1 year to BCG, tetanus, and measles immunisation; incidence of infectious diseases during infancy; and vertical HIV transmission. Analysis was by intention-to-treat. This trial is registered, number ISRCTN32849447. Findings Data were available at delivery for 2356 women, with 2345 livebirths; 2115 (90%) of liveborn infants remained in follow-up at 1 year of age. Neither albendazole nor praziquantel treatments aff ected infant response to BCG, tetanus, or measles immunisation. However, in infants of mothers with hookworm infection, albendazole treatment reduced interleukin-5 (geometric mean ratio 0·50, 95% CI 0·30–0·81, interaction p=0·02) and interleukin-13 (0·52, 0·34–0·82, 0·0005) response to tetanus toxoid. The rate per 100 person-years of malaria was 40·9 (95% CI 38·3–43·7), of diarrhoea was 134·1 (129·2–139·2), and of pneumonia was 22·3 (20·4–24·4). We noted no eff ect on infectious disease incidence for albendazole treatment (malaria [hazard ratio 0·95, 95% CI 0·79–1.14], diarrhoea [1·06, 0·96–1·16], pneumonia [1·11, 0·90–1·38]) or praziquantel treatment (malaria [1·00, 0·84–1·20], diarrhoea [1·07, 0·98–1·18], pneumonia [1·00, 0·80–1·24]). In HIV-exposed infants, 39 (18%) were infected at 6 weeks; vertical transmission was not associated with albendazole (odds ratio 0·70, 95% CI 0·35–1·42) or praziquantel (0·60, 0·29–1·23) treatment.
Factors affecting the infant antibody response to measles immunisation in Entebbe-Uganda
(BMC public health,, 2013) Kizito, Dennison; Tweyongyere, Robert; Namatovu, Alice; Webb, Emily L.; Muhangi, Lawrence; Lule, Swaib A.; Bukenya, Henry; Cose, Stephen; Elliott, Alison M.
Background: Vaccine failure is an important concern in the tropics with many contributing elements. Among them, it has been suggested that exposure to natural infections might contribute to vaccine failure and recurrent disease outbreaks. We tested this hypothesis by examining the influence of co-infections on maternal and infant measles-specific IgG levels. Methods: We conducted an observational analysis using samples and data that had been collected during a larger randomised controlled trial, the Entebbe Mother and Baby Study (ISRCTN32849447). For the present study, 711 pregnant women and their offspring were considered. Helminth infections including hookworm, Schistosoma mansoni and Mansonella perstans, along with HIV, malaria, and other potential confounding factors were determined in mothers during pregnancy and in their infants at age one year. Infants received their measles immunisation at age nine months. Levels of total IgG against measles were measured in mothers during pregnancy and at delivery, as well as in cord blood and from infants at age one year. Results: Among the 711 pregnant women studied, 66% had at least one helminth infection at enrolment, 41% had hookworm, 20% M. perstans and 19% S. mansoni. Asymptomatic malaria and HIV prevalence was 8% and 10% respectively. At enrolment, 96% of the women had measles-specific IgG levels considered protective (median 4274 mIU/ml (IQR 1784, 7767)). IgG levels in cord blood were positively correlated to maternal measles-specific IgG levels at delivery (r = 0.81, p < 0.0001). Among the infants at one year of age, median measles-specific IgG levels were markedly lower than in maternal and cord blood (median 370 mIU/ml (IQR 198, 656) p < 0.0001). In addition, only 75% of the infants had measles-specific IgG levels considered to be protective. In a multivariate regression analysis, factors associated with reduced measles-specific antibody levels in infancy were maternal malaria infection, infant malaria parasitaemia, infant HIV and infant wasting. There was no association with maternal helminth infection. Conclusion: Malaria and HIV infection in mothers during pregnancy, and in their infants, along with infant malnutrition, may result in reduction of the antibody response to measles immunisation in infancy. This re-emphasises the importance of malaria and HIV control, and support for infant nutrition, as these interventions may have benefits for vaccine efficacy in tropical settings.
Invasive Cattle Ticks in East Africa: Morphological and Molecular Confirmation of The Presence of Rhipicephalus Microplus in South‑Eastern Uganda
(Parasites & Vectors, 2020) Muhanguzi, Dennis; Byaruhanga, Joseph; Amanyire, Wilson; Ndekezi, Christian; Ochwo, Sylvester; Nkamwesiga, Joseph; Mwiine, Frank Norbert; Tweyongyere, Robert; Fourie, Josephus; Madder, Maxime; Schetters, Theo; Horak, Ivan; Juleff, Nick; Jongejan, Frans
Rhipicephalus microplus, an invasive tick species of Asian origin and the main vector of Babesia species, is considered one of the most widespread ectoparasites of livestock. The tick has spread from its native habitats on translocated livestock to large parts of the tropical world, where it has replaced some of the local populations of Rhipicephalus decoloratus ticks. Although the tick was reported in Uganda 70 years ago, it has not been found in any subsequent surveys. This study was carried out to update the national tick species distribution on livestock in Uganda as a basis for tick and tick-borne disease control, with particular reference to R. microplus.The study was carried out in Kadungulu, Serere district, south-eastern Uganda, which is dominated by small scale livestock producers. All the ticks collected from 240 cattle from six villages were identified microscopically. Five R. microplus specimens were further processed for phylogenetic analysis and species confirmation.The predominant tick species found on cattle was Rhipicephalus appendiculatus (86.9 %; n = 16,509). Other species found were Amblyomma variegatum (7.2 %; n = 1377), Rhipicephalus evertsi (2.3 %; n = 434) and R. microplus (3.6 %; n = 687). Phylogenetic analysis of the 12S rRNA, 16S rRNA and ITS2 gene sequences of R. microplus confirmed the morphological identification.It is concluded that R. microplus has replaced R. decoloratus in the sampled villages in Kadungulu sub-county, since the latter was not any longer found in this area. There is currently no livestock movement policy in force in Uganda, which could possibly limit the further spread of R. microplus ticks. Future surveys, but also retrospective surveys of museum specimens, will reveal the extent of distribution of R. microplus in Uganda and also for how long this tick has been present on livestock without being noticed.
Molecular detection and characterization of emerging pathogens of Rickettsia- felis and felis-like organisms from peri-domestic eas in Uganda
(Research Article, 2023) Eneku, Wilfred; Erima, Bernard; Maranda Byaruhanga, Anatoli; Nora, G. Cleary; Atim, Gladys; Tugume, Titus; Ukuli, Qouilazoni A.; Kibuuka, Hannah; Mworozi, Edison; Christina Douglas; Jeffrey W. Koehler; Michael E. Fricken; Biryomumaisho, Savino; Matovu, Enock; Tweyongyere, Robert; Wabwire-Mangen, Fred; Byarugaba, Denis K.
Background: Flea-borne spotted fever is an emerging zoonosis caused by Rikecttsia felis, a Gram-negative obligate intracellular bacterium. The agent is believed to be cosmopolitan, following the distribution pattern of its host and reservoir, Ctenocephalides felis. However, the epidemiology and public health risk it poses remains poorly understood in sub-Saharan Africa, including Uganda. Yersinia pestis, is primarily transmitted by rodent fleas, Xenopsylla cheopis, but other fleas, particularly C. felis, have vectoral capacity. They are neglected in Ugandan entomological surveillance and public health practices, particularly outside endemic foci of bubonic plague. Methods: We collected 14,641 fleas from domestic animals, rodents and homestead environment; compared their diversity and abundance. Pooled into 714 flea pools by species, collection time, host, and host species, 172 pools were selected based on seasons and analyzed for Yersinia pestis Pla genes, while 62 pools were tested for Rickettsia species gltA, ompA, and 17kDA genes by qPCR and Sanger sequencing. Results: Five flea species were identified from the collections: Ctenocephalides canis, C. felis, Echidnophaga gallinacea, Pulex irritans, and Xenopsylla cheopis. Ctenocephalides was the predominant genus, accounting for 84.8% of fleas collected, mostly found on dogs and goats. Except for P. irritans (which was found in Gulu district) the other four flea species were found across all districts, year-round, with higher numbers collected in dry seasons compared to rainy seasons (c2=47.64, df=20, p<0.001). Rattus rattus constituted 74% of rodents captured from human dwellings and was the only rodent species with fleas, where X. cheopis was the predominant species and E. gallinacea found on only three rodents. All 172 pools of fleas tested negative for Yersinia pestis. Of the 62 pools tested for Rickettsia spp., 29 (46.8%) were positive. Twenty-five PCR amplicons were successfully sequenced for 17kDa and two for ompA genes. Based on 17kDa, two were identified as R. felis from C. canis and 23 were R. asembonensis from multiple flea species, including C. canis collected goats and C. felis from cats. Conclusion: Our survey identified a high pooled detection rate (~50%) of Rickettsia spp. in fleas tested, suggesting a potential risk of human exposure and infection. Rickettsia felis and R. asembonensis were the predominant flea-borne Rickettsia spp. identified, with this study also representing the first report of Rickettsia spp. in E. gallinacea in Uganda.
Molecular detection of Coxiella burnetii in ticks collected from animals and the environment in Uganda
(Zoonoses and Public Health, 2024) Eneku, Wilfred; Erima, Bernard; Maranda Byaruhanga, Anatoli; Nora, Cleary; Atim, Gladys; Tugume, Titus; Ukuli, Qouilazoni Aquino; Kibuuka, Hannah; Mworozi, Edison; Tweyongyere, Robert; Christina, E. Douglas; Jeffrey, W. Koehler; Michael, E. von Fricken; Wabwire-Mangen, Fred; Byarugaba, Denis K.
Aims Coxiella burnetii is a highly infectious organism that is easily spread through aerosols causing Q fever in humans. Ticks can harbour and transmit C. burnetii to animals, contributing to disease maintenance. Our aim was to examine the presence of C. burnetii in ticks in Uganda. Methods and Results In this study, ticks were collected from five Ugandan districts and tested by real-time PCR for C. burnetii (Coxiella outer membrane protein 1 gene). A total of 859 tick pools (9602 individual ticks) were tested, and pool positivity for C. burnetii was 5.5% (n = 47). Pooled prevalence differed by district; the highest was Luwero (7.3%), then Gulu (6.6%), and Kasese had the lowest (1.3%). However, district variation was not statistically significant (Fisher's exact = 0.07). Ticks collected from dogs and cats had the highest positivity rates [23/47, (48.9%)] followed by livestock (cattle, goats, sheep, and pigs) [18/47, (38.3%)] and vegetation [6/47, (12.8%)]. Haemaphysalis elliptica had the highest infection rates, followed by Rhipicephalus appendiculatus, Amblyomma variegatum and Rhipicephalus decoloratus had similar prevalence. Conclusions Although ticks are not the primary transmitters of C. burnetii to humans, pathogen detection in ticks can be an indirect indicator of risk among animal hosts. Vulnerable populations, including occupations with close animal contact such as farming, butchery, and veterinary practice, have an increased risk of C. burnetii exposure. Veterinarians and clinicians should be aware that C. burnetii may cause human and animal illness in these regions.
Molecular epidemiology of Babesia species, Theileria parva, and Anaplasma marginale infecting cattle and the tick control malpractices in central and eastern Uganda
(Ticks and tick-borne diseases, 2018) Tayebwa, Dickson Stuart; Vudriko, Patrick; Tuvshintulga, Bumduuren; Guswanto, Azirwan; Budiman Nugraha, Arifin; Gantuya, Sambuu; El-Saber Batiha, Gaber; Musinguzi, Simon Peter; Komugisha, Mariam; Bbira, Jonh Son; Okwee-Acai, James; Tweyongyere, Robert; Wampande, Eddie M.; Byaruhanga, Joseph; Adjou Moumouni, Paul Franck; Sivakumar, Thillaiampalam; Yokoyama, Naoaki; Igarashi, Ikuo
East Coast fever, babesiosis, and anaplasmosis are the major tick-borne diseases affecting cattle productivity in Uganda. The emergence of acaricide-resistant ticks is suspected to have caused a rise in hemoparasites. This study sought to detect and characterize hemoparasites among farms in acaricide-failure hotspots of central as compared to the acaricide-failure naïve areas in eastern Uganda. Nested PCR assays were performed to determine the prevalences of Babesia bovis, Babesia bigemina, Theileria parva, and Anaplasma marginale in cattle blood samples sourced from randomly selected farms. Randomly selected isolates were sequenced to determine the genetic diversity of the parasites using the following marker genes: B. bovis spherical body protein 4, B. bigemina rhoptry-associated protein 1a, T. parva 104 kDa microneme-rhoptry antigen, and A. marginale major surface protein 5. Furthermore, partially and fully engorged adult ticks were collected for taxonomy, and tick-control practices were assessed using a semi-structured questionnaire. The prevalences of B. bigemina, T. parva, and A. marginale in cattle were 17.2, 65.1, and 22.0%, and 10.0, 26.5, and 3% in the central and eastern region, respectively. Whilst, B. bovis was not detected in the farms involved. The sequences for B. bigemina, T. parva, and A. marginale from the central region showed 99% identity with those from the eastern region. Of the 548 ticks collected, 319, 147, 76, and 6 were Rhipicephalus (Boophilus) decoloratus, Rhipicephalus appendiculatus, Amblyomma variegatum, and Rhipicephalus evertsi evertsi, respectively. The Rhipicephalus ticks were more abundant in the central, whereas A. variegatum ticks were more abundant in the eastern region. Tick control malpractices were found in both central and eastern Uganda, and 42 of the 56 surveyed farms lacked appropriate restraining facilities and so they utilized either ropes or a ‘boma’ (enclosure). In summary, B. bigemina, T. parva, A. marginale and their co-infections were more prevalent in the central than eastern region; even though, tick control malpractices were observed in both regions. Therefore, an urgent tick and TBD control strategy is needed.
Nanotechnological Solutions For Controlling Transmission And Emergence Of Antimicrobial-Resistant Bacteria, Future Prospects, And Challenges: A Systematic Review
(Journal of Nanoparticle Research, 2020) Ssekatawa, Kenneth; Byarugaba, Dennis K.; Kato, Charles D.; Ejobi, Francis; Tweyongyere, Robert; Lubwama, Michael; Kirabira, John Baptist; Wampande, Eddie M.
Globally, a high prevalence of multi-drug-resistant (MDR) bacteria, mostly methicillin-resistant Staphylococcus aureus and carbapenem-resistant Enterobacteriaceae, has been reported. Infections caused by such bacteria are expensive and hard to treat due to reduced efficient treatment alternatives. Centered on the current rate of antibiotics production and approvals, it is anticipated that by 2050 up to 10 million people could die annually due to MDR pathogens. To this effect, alternative strategies such as the use of nanotechnology to formulate nanobactericidal agents are being explored. This systematic review addresses the recent approaches, future prospects, and challenges of nanotechnological solutions for controlling transmission and emergence of antibiotic resistance. A comprehensive literature search of PubMed and BioMed Central databases from June 2018 to January 2019 was performed. The search keywords used were “use of nanotechnology to control antibiotic resistance” to extract articles published only in English encompassing all research papers regardless of the year of publication. PubMed and BioMed Central databases literature exploration generated 166 articles of which 49 full-text research articles met the inclusion guidelines. Of the included articles, 44.9%, 30.6%, and 24.5% reported the use of inorganic, hybrid, and organic nanoparticles, respectively, as bactericidal agents or carriers/enhancers of bactericidal agents. Owing to the ever-increasing prevalence of antimicrobial resistance to old and newly synthesized drugs, alternative approaches such as nanotechnology are highly commendable. This is supported by in vitro, ex vivo, and in vivo studies assessed in this review as they reported high bactericide efficacies of organic, inorganic, and hybrid nanoparticles.
Near-Complete Genome Sequences of Measles Virus Strains from 10 Years of Uganda Country-wide Surveillance
(Microbiology Resource Announcements, 2022) Namuwulya, Prossy; Bukenya, Henry; Tushabe, Phionah; Tweyongyere, Robert; Bwogi, Josephine; Cotten, Matthew; Phan, My V. T.
Measles remains a global health challenge despite the availability of a safe and effective vaccine. Sporadic outbreaks of measles virus infections continue in Uganda. We report eight near-complete genome sequences of measles virus strains from Uganda cases from 2011 to 2020, providing useful data for assessing vaccine escape and local/regional transmission.
Prevalence of Crimean-Congo haemorrhagic fever in livestock following a confrmed human case in Lyantonde district, Uganda
(Parasites & Vectors, 2023) Atim, Stella A.; Niebel, Marc; Vudriko, Patrick; Odongo, Steven; Balinandi, Stephen; Aber, Peace; Bameka, Ronald; Ademun, Anna R.; Masembe, Charles; Tweyongyere, Robert; Thomson, Emma C.
Crimean-Congo haemorrhagic fever (CCHF) is a tick-borne viral infection, characterized by haemorrhagic fever in humans and transient asymptomatic infection in animals. It is an emerging human health threat causing sporadic outbreaks in Uganda. We conducted a detailed outbreak investigation in the animal population following the death from CCHF of a 42-year-old male cattle trader in Lyantonde district, Uganda. This was to ascertain the extent of CCHF virus (CCHFV) circulation among cattle and goats and to identify affected farms and ongoing increased environmental risk for future human infections.
Prevalence of pathogenic Klebsiella pneumoniae based on PCR capsular typing harbouring carbapenemases encoding genes in Uganda tertiary hospitals
(Antimicrobial Resistance & Infection Control, 2021) Ssekatawa, Kenneth; Byarugaba, Denis K.; Nakavuma, Jesca L.; Kato, Charles D.; Ejobi, Francis; Tweyongyere, Robert; Wampande, Eddie M.
Background: Klebsiella pneumoniae is an opportunistic pathogen that has been implicated as one of commonest cause of hospital and community acquired infections. The K. pneumoniae infections have considerably contributed to morbidity and mortality in patients with protracted ailments. The capacity of K. pneumoniae to cause diseases depends on the presence of an array virulence factors. Coexistence and expression of virulence factors and genetic determinants of antibiotic resistance complicates treatment outcomes. Thus, emergence of pathogenic MDR K. pneumoniae poses a great threat to the healthcare system. However, the carriage of antibiotic resistance among pathogenic K. pneumoniae is yet to be investigated in Uganda. We sought to investigate the carbapenem resistance profiles and pathogenic potential based on capsular serotypes of K. pneumoniae clinical isolates. Methods: This was a cross sectional study involving use of archived Klebsiella pneumoniae isolates collected between January and December, 2019 at four tertiary hospitals in Uganda. All isolates were subject to antimicrobial susceptibility assays to determine phenotypic antibiotic resistance, pentaplex PCR to detect carbapenemases encoding genes and heptaplex PCR to identify capsular serotypes K1, K2, K3, K5, K20, K54 and K57. Results: The study found an overall phenotypic carbapenem resistance of 23.3% (53/227) and significantly higher genotypic resistance prevalence of 43.1% (98/227). Over all, the most prevalent gene was blaOXA-48-like (36.4%), followed by blaIMP-type (19.4%), blaVIM-type (17.1%), blaKPC-type (14.0%) and blaNDM-type (13.2%). blaVIM-type and blaOXA-48-like conferred phenotypic resistance in all isolates and 38.3% of isolates that harbored them respectively. Capsular multiplex PCR revealed that 46.7% (106/227) isolates were pathogenic and the predominantly prevalent pathotype was K5 (18.5%) followed by K20 (15.1%), K3 (7.1%), K2 (3.1%) and K1 (2.2%). Of the 106 capsular serotypes, 37 expressed phenotypic resistance; thus, 37 of the 53 carbapenem resistant K. pneumoniae were pathogenic. Conclusion: The high prevalence of virulent and antibiotic resistant K. pneumoniae among clinical isolates obtained from the four tertiary hospital as revealed by this study pose a great threat to healthcare. Our findings underline the epidemiological and public health risks and implications of this pathogen.
Retrospective study on cattle and poultry diseases in Uganda
(International Journal of Veterinary Science and Medicine, 2017) Byaruhanga, Joseph; Tayebwa, Dickson S.; Eneku, Wilfred; Afayoa, Mathias; Mutebi, Francis; Ndyanabo, Susan; Kakooza, Steven; Okwee-Acai, James; Tweyongyere, Robert; Wampande, Eddie M.; Vudriko, Patrick
Cattle and poultry enterprises are among the major contributors to food security and socioeconomic empowerment of households in Uganda. However, various diseases constrain their productivity. A two-year retrospective study between April 2012 and March 2014 was conducted using records for cattle and poultry diseases diagnosed at the Central Diagnostic Laboratory (CDL) to determine prevalent diseases in Uganda. The laboratory received 836 samples from poultry (36.3%) and cattle (63.7%). Of the 836 samples, 47.5% had a definitive diagnosis of disease causation. Most of the cattle and poultry diseases diagnosed were protozoan diseases (39.3%) followed by bacterial (21.4%), viral (17.1%), helminthiasis (11.1%), nutritional diseases (4%) and others (7.1%). For poultry, viral diseases (29.5%) and protozoan diseases (27.1%) especially newcastle disease (44.3%) and coccidiosis (100%) respectively, were the most diagnosed. While for cattle, hemo-protozoan parasites (52.1%) were the most prevalent, of which 92.9% were east coast fever infection. Bacterial infection (20.5%) in cattle were the second most diagnosed diseases and mastitis was the most diagnosed (46.2%). In summary, coccidioisis, collibacillosis, newcastle disease, gumboro disease, and avian helminthiasis were the most prevalent poultry diseases while in cattle, east coast fever, helminthiasis, mastitis, brucellosis and rabies were the most frequently diagnosed diseases. This study has identified the major diseases that hinder poultry and cattle production in Uganda. The data generated by CDL could be used for surveillance, monitoring and designing strategic interventions for control of poultry and cattle diseases in Uganda.
A review of phage mediated antibacterial applications
(Alexandria Journal of Medicine, 2021) Ssekatawa, Kenneth; Byarugaba, Denis K.; Kato, Charles D.; Wampande, Eddie M.; Ejobi, Francis; Tweyongyere, Robert; Nakavuma, Jesca L.
For over a decade, resistance to newly synthesized antibiotics has been observed worldwide. The challenge of antibiotic resistance has led to several pharmaceutical companies to abandon the synthesis of new drugs in fear of bacteria developing resistance in a short period hence limiting initial investment return. To this effect, alternative approaches such as the use of bacteriophages to treat bacterial infections are being explored. This review explores the recent advances in phage-mediated antibacterial applications and their limitations. Methods: We conducted a comprehensive literature search of PubMed, Lib Hub and Google Scholar databases from January 2019 to November 2019. The search key words used were the application of bacteriophages to inhibit bacterial growth and human phage therapy to extract full-text research articles and proceedings from International Conferences published only in English. Results: The search generated 709 articles of which 95 full-text research articles fulfilled the inclusion guidelines. Transmission Electron Microscopy morphological characterization conducted in 23 studies registered Myoviruses, Siphoviruses, Podoviruses, and Cytoviruses phage families while molecular characterization revealed that some phages were not safe to use as they harbored undesirable genes. All in vivo phage therapy studies in humans and model animals against multidrug-resistant (MDR) bacterial infection provided 100% protection. Ex vivo and in vitro phage therapy experiments exhibited overwhelming results as they registered high efficacies of up to 100% against MDR clinical isolates. Phage-mediated bio-preservation of foods and beverages and bio-sanitization of surfaces were highly successful with bacterial growth suppression of up to 100%. Phage endolysins revealed efficacies statistically comparable to those of phages and restored normal ethanol production by completely eradicating lactic acid bacteria in ethanol fermenters. Furthermore, the average multiplicity of infection was highest in ex vivo phage therapy (557,291.8) followed by in vivo (155,612.4) and in vitro (434.5).
Risk factors for Crimean-Congo Haemorrhagic Fever (CCHF) virus exposure in farming communities in Uganda
(Journal of Infection, 2022) Atim, Stella A.; Ashraf, Shirin; Ademun, Anna R.; Nakayiki, Teddy; Balinandi, Stephen; Nakanjako, Gladys; Abaasa, Andrew; Odongo, Steven; Esau, Martin; Kaleebu, Pontiano; Lutwama, Julius J.; Masembe, Charles; Lambe, Teresa; Tweyongyere, Robert
Crimean-Congo Haemorrhagic Fever (CCHF) is an emerging human-health threat causing sporadic outbreaks in livestock farming communities. However, the full extent and the risks associated with exposure of such communities has not previously been well-described. We collected blood samples from 800 humans, 666 cattle, 549 goats and 32 dogs in districts within and outside Ugandan cattle corridor in a cross-sectional survey, and tested for CCHFV-specific IgG antibodies using Enzyme-Linked Immunosorbent Assays. Sociodemographic and epidemiological data were recorded using structured questionnaire. Ticks were collected to identify circulating nairoviruses by metagenomic sequencing. CCHFV seropositivity was in 221/800 (27·6%) in humans, 612/666 (91·8%) in cattle, 413/549 (75·2%) in goats and 18/32 (56·2%) in dogs. Human seropositivity was associated with livestock farming (AOR=5·68, p<0·0001), age (AOR=2·99, p=0·002) and collecting/eating engorged ticks (AOR=2·13, p=0·004). In animals, seropositivity was higher in cattle versus goats (AOR=2·58, p<0·0001), female sex (AOR=2·13, p=0·002) and heavy tick infestation (>50 ticks: AOR=3·52, p=0·004). CCHFV was identified in multiple tick pools of Rhipicephalus appendiculatus.
Schistosoma mansoni coinfection is associated with high Plasmodium falciparum infection intensity among 10 -15 year old children living along the Albert Nile in Uganda
(Research Sqaure, 2024) Namulondo, Joyce; Nyangiri, Oscar Asanya; Kimuda, Magambo Phillip; Nambala, Peter; Nassuuna, Jacent; Kabagenyi, Joyce; Egesa, Moses; Nerima, Barbara; Biryomumaisho, Savino; Mugasa, Claire Mack; Alison, Elliott; Harry, Noyes; Tweyongyere, Robert; Matovu, Enock; Mulindwa, Julius
Background: Malaria and schistosomiasis are important parasitic diseases. Coinfections of these have been reported in areas endemic to both parasites. The aim of this study was to determine the association between Schistosoma mansoni (S. mansoni) and Plasmodium falciparum (P. falciparum) infection intensities among school age children living along the Albert Nile. Methods: A cross sectional study of 210 children aged 10–15 years, was conducted in selected sites along the Albert Nile in Pakwach District in northwest Uganda. The Circulating Anodic Antigen (CAA) test and quantitative PCR (qPCR) were used to test for S. mansoni infection intensity and quantitative PCR used to test for P. falciparum infection intensity. Results: Of the 210 study particpants, 76.2% (160/210) were malaria positive whereas 91% (191/210) were S. mansoni positive. There were only 1% (3/210) infections of each of Necator americanus and Strongyloides stercolaris. Of the P. falciparum positive children 57.5% (92/160) were male; on the other hand 53.4% (102/191) of the S. mansoni positive children were male. Overall, 150 of the 210 children tested (71%) had co-infection with both P. falciparum and S. mansoni. There was a significant association (p-value = 7.306e-10, r2 = 0.17) between P. falciparum qPCR Ct-value and S. mansoni qPCR Ct-value. There was a significant association (p-value = 7.306e-10, r2 = 0.17) between P. falciparum intensity (qPCR Ct-value) and S. mansoni intensity (qPCR Ct-value) among the children test. Conclusions: By molecular detection, this study observed a high prevalence of P. falciparum among the school age children (10–15 years) living in the S. mansoni endemic hotspots along the Albert-Nile region of Pakwach district, northwestern Uganda.

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