Browsing by Author "Mboera, Leonard E.G."

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Seroprevalence and associated risk factors of chikungunya, dengue, and zika in eight districts in Tanzania
(Elsevier Ltd, 2021) Mwanyika, Gaspary O.; Sindato, Calvin; Rugarabamu, Sima; Rumisha, Susan F.; Karimuribo, Esron D.; Misinzo, Gerald; Rweyemamu, Mark M.; Hamid, Muzamil M. Abdel; Haider, Najmul; Vairo, Francesco; Kock, Richard; Mboera, Leonard E.G.
Background: This study was conducted to determine the seroprevalence and risk factors of chikungunya (CHIKV), dengue (DENV), and Zika (ZIKV) viruses in Tanzania. Methods: The study covered the districts of Buhigwe, Kalambo, Kilindi, Kinondoni, Kondoa, Kyela, Mvomero, and Ukerewe in Tanzania. Blood samples were collected from individuals recruited from house- holds and healthcare facilities. An ELISA was used to screen for immunoglobulin G antibodies against CHIKV, DENV, and ZIKV. Results: A total of 1818 participants (median age 34 years) were recruited. The overall CHIKV, DENV, and ZIKV seroprevalence rates were 28.0%, 16.1%, and 6.8%, respectively. CHIKV prevalence was highest in Buhigwe (46.8%), DENV in Kinondoni (43.8%), and ZIKV in Ukerewe (10.6%) and Mvomero (10.6%). Increas- ing age and frequent mosquito bites were significantly associated with CHIKV and DENV seropositivity ( P < 0.05). Having piped water or the presence of stagnant water around the home ( P < 0.01) were as- sociated with higher odds of DENV seropositivity. Fever was significantly associated with increased odds of CHIKV seropositivity ( P < 0.001). Visiting mines had higher odds of ZIKV seropositivity ( P < 0.05). Conclusions: These findings indicate that DENV, CHIKV, and ZIKV are circulating in diverse ecological zones of Tanzania. There is a need to strengthen the control of mosquito-borne viral diseases in Tanzania.
A spatial analysis of Rift Valley Fever Virus seropositivity in domestic ruminants in Tanzania
(PLOS ONE, 2015-07-10) Sindato, Calvin; Pfeiffer, Dirk U.; Karimuribo, Esron D.; Mboera, Leonard E.G.; Rweyemamu, Mark M.; Paweska, Janusz T.
Rift Valley fever(RVF) is an acute arthropod-borne viral zoonotic disease primarily occurring in Africa.Since RVF-like disease was reported in Tanzaniain1930,outbreaks of the disease have been reported mainly from the eastern ecosystem of the Great Rift Valley. This cross-sectional study was carried out to describe the variation in RVF virus (RVFV) seropositivity in domestic ruminants between selected villages in the eastern and western Rift Valley ecosystems in Tanzania, and identify potential risk factors. Three study villages were purposively selected from each of the two Rift Valley ecosystems. Serum samples from randomly selected domestic ruminants (n=1,435) were tested for the presence of specific immunoglobulin G(IgG) and M(IgM) ,using RVF enzyme-linked immunosorbent assay methods .Mixed effects logistic regression modelling was used to investigate the association between potential risk factors and RVFV seropositivity. The overall RVFV seroprevalence (n=1,435) in domestic ruminants was 25.8% and species specific seroprevalence was 29.7%, 27.7% and 22.0% in sheep (n=148), cattle (n=756) and goats (n=531), respectively. The odds of seropositivity were significantly higher in animals sampled from the villages in the eastern than those in the western Rift Valley ecosystem (OR=1.88,CI: 1.41,2.51; p<0.001) , in animals sampled from villages with soils of good than those with soils of poor water holding capacity (OR=1.97; 95%CI:1.58,3.02;p<0.001), and in animals which had been introduced than in animals born within the herd (OR=5.08,CI:2.74, 9.44;p<0.001). Compared with animals aged 1–2 years, those aged 3 and 4–5 years had 3.40 (CI:2.49,4.64;p<0.001) and 3.31 (CI:2.27,4.82,p<0.001) times the odds of seropositivity. The findings confirm exposure to RVFV in all the study villages, but with a higher prevalence in the study villages from the eastern Rift Valley ecosystem.