Reservoir dynamics of rabies in Southeast Tanzania and the roles of cross-species transmission and domestic dog vaccination

1) Understanding the role of different species in the transmission of multi-host pathogens, such as rabies virus, is vital for effective control strategies. Across most of sub-Saharan Africa domestic dogs (Canis familiaris) are considered the reservoir for rabies, but the role of wildlife has been long debated. Here we explore the multi-host transmission dynamics of rabies across southeast Tanzania. 2) Between January 2011 and July 2019 data on probable rabies cases were collected in the regions of Lindi and Mtwara. Hospital records of animal-bite patients presenting to healthcare facilities were used as sentinels for animal contact tracing. The timing, location and species of probable rabid animals was used to reconstruct transmission trees to infer who infected whom and the relative frequencies of within-and between-species transmission. 3) During the study, 688 probable human rabies exposures were identified, resulting in 47 deaths. Of these exposures, 389 were from domestic dogs (56.5%) and 262 from jackals (38.1%). Over the same period 549 probable animal rabies cases were traced: 303 in domestic dogs (55.2%) and 221 in jackals (40.3%). 4) Although dog-to-dog transmission was most commonly inferred (40.5% of transmission events), a third of inferred events involved wildlife-to-wildlife transmission (32.6%) and evidence suggested some sustained transmission chains within jackal populations. 5) A steady decline in probable rabies cases in both humans and animals coincided with the implementation of widespread domestic dog vaccination during the first six years of the study. Following the lapse of this programme dog rabies cases began to increase in one of the northernmost districts. 6) Synthesis and applications: in southeast Tanzania, despite a relatively high incidence of rabies in wildlife and evidence of wildlife-to-wildlife transmission, domestic dogs remain essential to the reservoir of infection. Continued dog vaccination alongside improved surveillance would allow a fuller understanding of the role of wildlife in maintaining transmission in this area. Nonetheless, dog vaccination clearly suppressed rabies in both domestic dog and wildlife populations, reducing both public health and conservation risks and, if sustained, has potential to eliminate rabies from this region

Effect of pond management on prevalence of intestinal parasites in Nile Tilapia (Oreochromis niloticus) under small scale fish farming systems in Morogoro, Tanzania

Journal ArticleA cross-sectional study was conducted in small scale fish farming systems in Morogoro urban and rural area between December 2007 and February 2008 to determine the effect of pond management on prevalence of intestinal parasites in Nile Tilapia (Oreochromis niloticus). Water physicochemical parameters in fish ponds and the risk factors for intestinal parasites were determined. Information on pond type and cleanness, feeding and general pond management was also gathered through questionnaires and participant observations during the sample collection. One fifty three adult O. niloticus from 13 ponds were examined. It was found that most ponds (69%) were small and of earthen type, 77% were clean and were using river water. Up to 92% of farmers changed pond water regularly and almost all farmers reported to use maize bran as the main feed for fish. Farmers used different types of animal manure to fertilize the ponds. The observed water physicochemical levels were within the normal range for fish water ponds as recommended by FAO. The prevalence of intestinal parasites was 16.3%. Specifically, 15% of fish had Eimeria oocysts while 1.3% had unidentified flukes. Prevalence of parasites was significantly higher (P < 0.05) in ponds located in rural (18.7%) than in urban areas (6.7%). Significantly (P<0.05) higher prevalence of parasites was observed in fish ponds using river water (18.8%) than in ponds using rain water (0%). Pond type was also a risk factor as there was a significantly (P < 0.05) higher parasite infection rates in earthen ponds (20.9%) than in fish reared in concrete ponds (4.7%). It is concluded that earthen fishponds, keeping fish in rural areas and using river water in ponds predisposes fish to intestinal parasites. Good water quality management and proper fish husbandry techniques will eliminate most parasitic infection and improve fish production.Higher Student Loan Body of Tanzani

Effect of pond management on prevalence of intestinal parasites in Nile Tilapia (Oreochromis niloticus) under small scale fish farming systems in Morogoro, Tanzania

Journal ArticleA cross-sectional study was conducted in small scale fish farming systems in Morogoro urban and rural area between December 2007 and February 2008 to determine the effect of pond management on prevalence of intestinal parasites in Nile Tilapia (Oreochromis niloticus). Water physicochemical parameters in fish ponds and the risk factors for intestinal parasites were determined. Information on pond type and cleanness, feeding and general pond management was also gathered through questionnaires and participant observations during the sample collection. One fifty three adult O. niloticus from 13 ponds were examined. It was found that most ponds (69%) were small and of earthen type, 77% were clean and were using river water. Up to 92% of farmers changed pond water regularly and almost all farmers reported to use maize bran as the main feed for fish. Farmers used different types of animal manure to fertilize the ponds. The observed water physicochemical levels were within the normal range for fish water ponds as recommended by FAO. The prevalence of intestinal parasites was 16.3%. Specifically, 15% of fish had Eimeria oocysts while 1.3% had unidentified flukes. Prevalence of parasites was significantly higher (P < 0.05) in ponds located in rural (18.7%) than in urban areas (6.7%). Significantly (P<0.05) higher prevalence of parasites was observed in fish ponds using river water (18.8%) than in ponds using rain water (0%). Pond type was also a risk factor as there was a significantly (P < 0.05) higher parasite infection rates in earthen ponds (20.9%) than in fish reared in concrete ponds (4.7%). It is concluded that earthen fishponds, keeping fish in rural areas and using river water in ponds predisposes fish to intestinal parasites. Good water quality management and proper fish husbandry techniques will eliminate most parasitic infection and improve fish production.Higher Student Loan Body of Tanzani

Effect of pond management on prevalence of intestinal parasites in Nile Tilapia (Oreochromis niloticus) under small scale fish farming systems in Morogoro, Tanzania

Journal ArticleA cross-sectional study was conducted in small scale fish farming systems in Morogoro urban and rural area between December 2007 and February 2008 to determine the effect of pond management on prevalence of intestinal parasites in Nile Tilapia (Oreochromis niloticus). Water physicochemical parameters in fish ponds and the risk factors for intestinal parasites were determined. Information on pond type and cleanness, feeding and general pond management was also gathered through questionnaires and participant observations during the sample collection. One fifty three adult O. niloticus from 13 ponds were examined. It was found that most ponds (69%) were small and of earthen type, 77% were clean and were using river water. Up to 92% of farmers changed pond water regularly and almost all farmers reported to use maize bran as the main feed for fish. Farmers used different types of animal manure to fertilize the ponds. The observed water physicochemical levels were within the normal range for fish water ponds as recommended by FAO. The prevalence of intestinal parasites was 16.3%. Specifically, 15% of fish had Eimeria oocysts while 1.3% had unidentified flukes. Prevalence of parasites was significantly higher (P < 0.05) in ponds located in rural (18.7%) than in urban areas (6.7%). Significantly (P<0.05) higher prevalence of parasites was observed in fish ponds using river water (18.8%) than in ponds using rain water (0%). Pond type was also a risk factor as there was a significantly (P < 0.05) higher parasite infection rates in earthen ponds (20.9%) than in fish reared in concrete ponds (4.7%). It is concluded that earthen fishponds, keeping fish in rural areas and using river water in ponds predisposes fish to intestinal parasites. Good water quality management and proper fish husbandry techniques will eliminate most parasitic infection and improve fish production.Higher Student Loan Body of Tanzani

Socio-economic values of wetland resources around Lake Manyara, Tanzania: assessment of environmental threats and local community awareness on environmental degradation and their effects

Understanding local people’s socio-economic values of wetlands and traditional mechanisms of managing natural resources forms the basis of conserving them. Wetlands have frequently been developed for short-term economic gains that destroy their ecological values and environmental services in the long term. A study was carried out to assess socio-economic values of the wetland resources, environmental threats around Lake Manyara and local community awareness on causes of environmental changes, degradation in the wetlands and their effects using 80 respondents. Field surveys, interviews, questionnaires and direct observation were used in data collection. It was found that local community was aware on the ecosystem services accrued from the wetlands which were unsustainably used. However, environmental degradation due to unsustainable agriculture, overgrazing, deforestation, urbanization and mining was rampant which had resulted to soil erosion, reduced water availability, wildlife mortality and frequent dry up of Lake Manyara and rivers. In order to protect the lake basin; controlled human activities, land use and water resources within the catchment are to be done in cooperation between the government departments, local authorities and the general local community around. Key words: Ecosystem services; rivers; Lake Manyara; wetland; agriculture DOI: 10.3126/jowe.v4i0.4153Journal of Wetlands Ecology, (2010) Vol. 4, pp 83-101 </jats:p

Reservoir dynamics of rabies in south-east Tanzania and the roles of cross-species transmission and domestic dog vaccination

1. Understanding the role of different species in the transmission of multi-host pathogens, such as rabies virus, is vital for effective control strategies. Across most of sub-Saharan Africa domestic dogs Canis familiaris are considered the reservoir for rabies, but the role of wildlife has been long debated. Here we explore the multi-host transmission dynamics of rabies across south-east Tanzania. 2. Between January 2011 and July 2019, data on probable rabies cases were collected in the regions of Lindi and Mtwara. Hospital records of animal-bite patients presenting to healthcare facilities were used as sentinels for animal contact tracing. The timing, location and species of probable rabid animals were used to reconstruct transmission trees to infer who infected whom and the relative frequencies of within- and between-species transmission. 3. During the study, 688 probable human rabies exposures were identified, resulting in 47 deaths. Of these exposures, 389 were from domestic dogs (56.5%) and 262 from jackals (38.1%). Over the same period, 549 probable animal rabies cases were traced: 303 in domestic dogs (55.2%) and 221 in jackals (40.3%), with the remainder in domestic cats and other wildlife species. 4. Although dog-to-dog transmission was most commonly inferred (40.5% of transmission events), a third of inferred events involved wildlife-to-wildlife transmission (32.6%), and evidence suggested some sustained transmission chains within jackal populations. 5. A steady decline in probable rabies cases in both humans and animals coincided with the implementation of widespread domestic dog vaccination during the first 6 years of the study. Following the lapse of this program, dog rabies cases began to increase in one of the northernmost districts. 6. Synthesis and applications. In south-east Tanzania, despite a relatively high incidence of rabies in wildlife and evidence of wildlife-to-wildlife transmission, domestic dogs remain essential to the reservoir of infection. Continued dog vaccination alongside improved surveillance would allow a fuller understanding of the role of wildlife in maintaining transmission in this area. Nonetheless, dog vaccination clearly suppressed rabies in both domestic dog and wildlife populations, reducing both public health and conservation risks and, if sustained, has potential to eliminate rabies from this region.</p