Browsing by Author "Ukuli, Qouilazoni A."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    Wide distribution of Mediterranean and African spotted fever agents and the first identification of Israeli spotted fever agent in ticks in Uganda
    (PLOS NEGLECTED TROPICAL DISEASES, 2023) Eneku, Wilfred; Erima, Bernard; Maranda Byaruhanga, Anatoli; Atim, Gladys; Tugume, Titus; Ukuli, Qouilazoni A.; Kibuuka, Hannah; Mworozi, Edison; Christina, Douglas; Jeffrey, W. Koehler; Nora, G. Cleary; Michael, E. von Fricken; Tweyongyere, Robert; Wabwire-Mangen, Fred; Karuhize Byarugaba, Denis
    Rickettsia microorganisms are causative agents of several neglected emerging infectious diseases in humans transmitted by arthropods including ticks. In this study, ticks were collected from four geographical regions of Uganda and pooled in sizes of 1–179 ticks based on location, tick species, life stage, host, and time of collection. Then, they were tested by real-time PCR for Rickettsia species with primers targeting gltA, 17kDa and ompA genes, followed by Sanger sequencing of the 17kDa and ompA genes. Of the 471 tick pools tested, 116 (24.6%) were positive for Rickettsia spp. by the gltA primers. The prevalence of Rickettsia varied by district with Gulu recording the highest (30.1%) followed by Luwero (28.1%) and Kasese had the lowest (14%). Tick pools from livestock (cattle, goats, sheep, and pigs) had the highest positivity rate, 26.9%, followed by vegetation, 23.1%, and pets (dogs and cats), 19.7%. Of 116 gltA-positive tick pools, 86 pools were positive using 17kDa primers of which 48 purified PCR products were successfully sequenced. The predominant Rickettsia spp. identified was R. africae (n = 15) in four tick species, followed by R. conorii (n = 5) in three tick species (Haemaphysalis elliptica, Rhipicephalus appendiculatus, and Rh. decoloratus). Rickettsia conorii subsp. israelensis was detected in one tick pool. These findings indicate that multiple Rickettsia spp. capable of causing human illness are circulating in the four diverse geographical regions of Uganda including new strains previously known to occur in the Mediterranean region. Physicians should be informed about Rickettsia spp. as potential causes of acute febrile illnesses in these regions. Continued and expanded surveillance is essential to further identify and locate potential hotspots with Rickettsia spp. of concern.