Browsing by Author "Clausen, Peter-Henning"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    First Report of the Occurrence of Trichinella- Specific Antibodies in Domestic Pigs in Central and Eastern Uganda
    (PLoS ONE, 2016) Roesel, Kristina; Nockler, Karsten; Baumann, Maximilian P. O.; Fries, Reinhard; Dione, Michel M.; Clausen, Peter-Henning; Grace, Delia
    Previous research on trichinellosis in Africa focused on isolating Trichinella from wildlife while the role of domestic pigs has remained highly under-researched. Pig keeping in Uganda is historically recent, and evidence on zoonotic pig diseases, including infection with Trichinella species, is scarce. A cross-sectional survey on Trichinella seroprevalence in pigs was conducted in three districts in Central and Eastern Uganda from April 2013 to January 2015. Serum from a random sample of 1125 pigs from 22 villages in Eastern and Central Uganda was examined to detect immunoglobulin G (IgG) against any Trichinella spp. using a commercially available ELISA based on excretory-secretory antigen. ELISA positive samples were confirmed using Western Blot based on somatic antigen of Trichinella spiralis as recommended in previous validation studies. Diaphragm pillar muscle samples (at least 5 g each) of 499 pigs from areas with high ELISA positivity were examined using the artificial digestion method. Overall, 78 of all 1125 animals (6.9%, 95% CI: 5.6±8.6%) tested positive for antibodies against Trichinella spp. in the ELISA at significantly higher levels in Kamuli district compared to Masaka and Mukono districts. Thirty-one percent of the ELISA positive samples were confirmed IgG positive by the Western Blot leading to an overall seroprevalence of 2.1% (95% CI: 1.4±3.2%). The large proportion of ELISA positive samples that could not be confirmed using Western blot may be the result of cross-reactivity with other gastrointestinal helminth infections or unknown host-specific immune response mechanisms in local pig breeds in Uganda. Attempts to isolate muscle larvae for species determination using the artificial digestion method were unsuccessful. Due to the large number of muscle samples examined we are confident that even if pigs are infected, the larval burden in pork is too low to pose a major risk to consumers of developing trichinellosis. This was the first large systematic field investigation of Trichinella infection in domestic pigs in Uganda
  • Thumbnail Image
    Item
    Knowledge, attitudes and practices of pork consumers in Uganda
    (Global Food Security, 2019) Roesela, Kristina; Ejobi, Francis; Dione, Michel; Pezo, Danilo; Ouma, Emily; Kungu, Joseph; Clausen, Peter-Henning; Grace, Delia
    Pig production is thriving in Uganda and the demand for pork is increasing, therefore offering potential for increased income from pig production and marketing. The consumers’ preferences determine and potentially drive this demand but are largely unknown in the context of Uganda. As part of a multi-disciplinary assessment of smallholder pig value chains we investigated these preferences in one of the four thematic subgroups with 292 smallholder pig farmers. In addition, 79 consumers in Kampala, the main pork market outlet in Uganda, were included. Using participatory methods and considering that pig keepers are also consumers, we describe drivers for and taboos around eating pork, the role of pork in peoples’ diets compared to other livestock-derived foods, important attributes when buying pork, the risk of pig feeds competing with human food as well as knowledge, attitudes and practices around pig zoonoses.
  • Thumbnail Image
    Item
    Prevalence and risk factors for gastrointestinal parasites in small-scale pig enterprises in Central and Eastern Uganda
    (Parasitology Research, 2017) Roesel, Kristina; Dohoo, Ian; Baumann, Maximilian; Dione, Michel; Grace, Delia; Clausen, Peter-Henning
    In Eastern Africa, small-scale pig keeping has emerged as a popular activity to generate additional household income. Infections of pigs with gastrointestinal helminths can limit production output, increase production costs, and pose zoonotic risks. A cross-sectional, community-based study in three districts in Eastern and Central Uganda examined the prevalence of gastrointestinal helminthes and associated risk factors in 932 randomly sampled pigs. Using the combined sedimentation-flotation method, 61.4 % (58.2–64.5 %, 95 % confidence interval [CI]) tested positive for one or more gastrointestinal helminths, namely, strongyles (57.1 %, 95 % CI), Metastrongylus spp. (7.6 %, 95 % CI), Ascaris suum (5.9 %, 95 % CI), Strongyloides ransomi (4.2 %, 95 % CI), and Trichuris suis (3.4 %, 95 % CI). Coccidia oocysts were found in 40.7 % of all pigs sampled (37.5–44.0 %, 95 % CI). Significant differences across the three districts were observed for the presence of A. suum (p < 0.001), Metastrongylus spp. (p = 0.001), S. ransomi (p = 0.002), and coccidia oocysts (p = 0.05). All animals tested negative for Fasciola spp. and Balantidium coli. Thirty-five variables were included in univariable analyses with helminth infection as the outcome of interest. A causal model was generated to identify relationships among the potential predictors, and consequently, seven variables with p ≤ 0.15 were included in a multivariable analysis for helminth infection. The final regression models showed that routine management factors had a greater impact on the prevalence of infection than regular, preventive medical treatment or the level of confinement. Factors that negatively correlated with gastrointestinal infection were the routine removal of manure and litter from pig pens (p ≤ 0.05, odds ratio [OR] = 0.667) and the routine use of disinfectants (p ≤ 0.05, OR = 0.548).
  • Thumbnail Image
    Item
    A review of recent research on Theileria parva: Implications for the infection and treatment vaccination method for control of East Coast fever
    (Transboundary and emerging diseases, 2020) Bishop, Richard P.; Odongo, David; Ahmed, Jabbar; Mwamuye, Micky; Nanteza, Anne; Lubega, George; Gwakisa, Paul; Clausen, Peter-Henning; Obara, Isaiah
    The infection and treatment (ITM) live vaccination method for control of Theileria parva infection in cattle is increasingly being adopted, particularly in Maasai pastoralist systems. Several studies indicate positive impacts on human livelihoods. Importantly, the first detailed protocol for live vaccine production at scale has recently been published. However, quality control and delivery issues constrain vaccination sustainability and deployment. There is evidence that the distribution of T. parva is spreading from endemic areas in East Africa, North into Southern Sudan and West into Cameroon, probably as a result of anthropogenic movement of cattle. It has also recently been demonstrated that in Kenya, T. parva derived from cape buffalo can ‘breakthrough’ the immunity induced by ITM. However, in Tanzania, breakthrough has not been reported in areas where cattle co-graze with buffalo. It has been confirmed that buffalo in northern Uganda national parks are not infected with T. parva and R. appendiculatus appears to be absent, raising issues regarding vector distribution. Recently, there have been multiple field population genetic studies using variable number tandem repeat (VNTR) sequences and sequencing of antigen genes encoding targets of CD8+ T-cell responses. The VNTR markers generally reveal high levels of diversity. The antigen gene sequences present within the trivalent Muguga cocktail are relatively conserved among cattle transmissible T. parva populations. By contrast, greater genetic diversity is present in antigen genes from T. parva of buffalo origin. There is also evidence from several studies for transmission of components of stocks present within the Muguga cocktail, into field ticks and cattle following induction of a carrier state by immunization. In the short term, this may increase live vaccine effectiveness, through a more homogeneous challenge, but the long-term consequences are unknown.