Browsing by Author "Kasanga, Christopher"

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Brucellosis testing patterns at health facilities in Arusha region, northern Tanzania
(Plos one, 2022-03-23) Yapi, Richard; Lukambagire, AbdulHamid; Shirima, Gabriel; Shayo, Damas; Mathew, Coletha; Kasanga, Christopher; Mmbaga, Blandina; Kazwala, Rudovick; Halliday, Jo
Background Brucellosis is listed as one of six priority zoonoses in Tanzania’s One Health strategic plan which highlights gaps in data needed for the surveillance and estimation of human brucellosis burdens. This study collected data on current testing practices and test results for human brucellosis in Arusha region, northern Tanzania. Methods Retrospective data were extracted from records at 24 health facilities in Arusha region for the period January 2012 to May 2018. Data were captured on: the test reagents used for brucellosis, procurement and testing protocols, the monthly number of patients tested for brucellosis and the monthly number testing positive. Generalised linear mixed models were used to evaluate relationships between health facility characteristics and the probability that brucellosis testing was conducted in a given month, and the proportion of individuals testing positive. Results Four febrile Brucella agglutination tests were used widely. The probability of testing for brucellosis in a given month was significantly associated with an interaction between year of testing and facility ownership. Test probability increased over time with more pronounced increases in privately owned as compared to government facilities. The proportion of individuals testing positive for brucellosis was significantly associated with facility type and district, with individuals tested in hospitals in Meru, Monduli and Ngorongoro districts more likely to test positive. Conclusions Febrile Brucella agglutination tests, known for their poor performance, were the mainstay of brucellosis testing at health facilities in northern Tanzania. The study indicates that historical data on human brucellosis in Arusha and other regions are likely to provide an inaccurate measure of true disease burden due to poor performance of the tests used and variation in testing practices. Measures to address these identified shortcomings could greatly improve quality of testing and surveillance data on brucellosis and ultimately inform prevention and control of this priority disease.
Detection of peste des petits ruminants and concurrent secondary diseases in sheep and goats in Ngorongoro district, Tanzania
(Springer, 2018-11-15) Kgotlele, Tebogo; Chota, Andrew; Chubwa, Choby; Nyasebwa, Obed; Lyimo, Beatus; Torsson, Emeli; Karimuribo, Esron; Kasanga, Christopher; Wensman, Jonas; Misinzo, Gerald; Shirima, Gabriel; Kusiluka, Lughano
Small ruminants play an important role in the livelihoods of resource-constrained communities. This study was initiated because of a massive outbreak of a respiratory disease in sheep and goats in Loliondo area in Ngorongoro district of Arusha region in Tanzania in 2016. During flock examination, a total of 240 serum samples and 61 nasal swabs were collected. Antibodies to small ruminant morbillivirus, causative agent of peste des petits ruminants (PPR), were detected from sera using a competitive enzyme-linked immunosorbent assay. A multiplex reverse transcription real-time polymerase chain reaction assay was used to detect four pathogens: small ruminant morbillivirus, Mycoplasma capricolum subspecies capripneumoniae, Pasteurella multocida, and Capripoxvirus from the nasal swabs. Overall seroprevalence of PPR was 74.6%, with all four pathogens detected from nasal swabs. Co-infections of small ruminant morbillivirus and Mycoplasma capricolum subspecies capripneumoniae, small ruminant morbillivirus and Capripoxvirus, small ruminant morbillivirus and Pasteurella multocida, and Mycoplasma capricolum subspecies capripneumoniae and Capripoxvirus were also detected. Presence of PPR and the other diseases in this study provided insight into the severity of the outbreak in sheep and goats in Ngorongoro district. Thus, laboratory confirmation is critical for prompt and appropriate interventions to be made for control of diseases in sheep and goats with similar clinical signs. The findings also call for research into development of combined vaccines targeting common diseases of small ruminants in Tanzania.
Factors associated with infectious bursal disease vaccination failure in Dar es salaam, Tanzania
(Journal of Veterinary Medicine and Animal Health, 2020-09) Saidi, Rukia; Shirima, Gabriel; Buza, Joram; Kasanga, Christopher
Infectious bursal disease (IBD) is a viral infection that affects young chicks. The IBD outbreaks in vaccinated chickens are reported in Tanzania frequently. The current study was conducted to find out the possible causes of vaccination failure focusing on knowledge and practices of vaccine sellers and users, the immunogenic potential of currently used vaccine and the phylogenetic relationship between the vaccine and the field strains. A cross-sectional study was performed to gather information on knowledge and practices from 384 poultry farmers and 20 veterinary outlets in Dar es Salaam. Results revealed inadequate knowledge of farmers in vaccine handling and administration and also breaches in the cold chain maintenance by vaccine sellers was apparent. A total of 60 chicks were experimentally vaccinated with Virgo 7 strain vaccine and titers of induced antibodies assessed. The vaccine induced adequate antibodies against IBDV, confirming its immunogenic efficacy. Isolated nucleic acids from the vaccine and field strains were sequenced and result shows that IBDV field isolates, are genetically different from the vaccine strains used in the country. The field isolates belong to the vvIBDV African types, while the vaccines belong to the vvIBDV European/Asian or classical virulent types. Putting together results from this study reveals multiple possible reasons which may contribute to vaccine failures. These include poor vaccine handling by farmers and vaccine sellers and the genetic disparity between the field and vaccine strains. It is therefore recommended that veterinary regulatory authorities should ensure good vaccine handling practices and considering local virus isolates during vaccine development.
Performance characteristics and costs of serological tests for brucellosis in a pastoralist community of northern Tanzania
(Springer Nature Limited, 2021-03-09) Lukambagire, AbdulHamid; Mendes, Ângelo; Bodenham, Rebecca; McGiven, John; Mkenda, Nestory; Mathew, Coletha; Rubach, Matthew; Sakasaka, Philoteus; Shayo, Davis; Maro, Venance; Shirima, Gabriel; Kasanga, Christopher; Kazwala, Rudovick; Halliday, Jo; Mmbaga, Blandina
The control of brucellosis across sub-Saharan Africa is hampered by the lack of standardized testing and the use of tests with poor performance. This study evaluated the performance and costs of serological assays for human brucellosis in a pastoralist community in northern Tanzania. Serum collected from 218 febrile hospital patients was used to evaluate the performance of seven index tests, selected based on international recommendation or current use. We evaluated the Rose Bengal test (RBT) using two protocols, four commercial agglutination tests and a competitive enzyme-linked immunosorbent assay (cELISA). The sensitivity, specificity, positive predictive value, negative predictive value, Youden’s index, diagnostic accuracy, and per-sample cost of each index test were estimated. The diagnostic accuracy estimates ranged from 95.9 to 97.7% for the RBT, 55.0 to 72.0% for the commercial plate tests, and 89.4% for the cELISA. The per-sample cost range was $0.69–$0.79 for the RBT, $1.03–$1.14 for the commercial plate tests, and $2.51 for the cELISA. The widely used commercial plate tests performed poorly and cost more than the RBT. These findings provide evidence for the public health value of discontinuing the use of commercial agglutination tests for human brucellosis in Tanzania.