Seropositivity of Leptospira in rodents, shrews, and domestic animals in Unguja, Tanzania

Background: Leptospirosis is one of the most commonly neglected zoonoses in developing nations including Tanzania. This study aims to find out the seroprevalence of leptospirosis in rodents, shrews, and domestic animals in different regions in Unguja Island, Tanzania.  Methods: A cross-sectional study was carried out from January to April 2022. The blood samples were collected from rodents and shrews (n=248), cattle (n=247), goats (n=130), sheep (n=32), and dogs (n=80). The blood samples were allowed to clot in a slanted position and serum samples were harvested. A microscopic agglutination test (MAT) was performed on the sera to check for leptospiral antibodies using five Leptospira serovars as antigens (Sokoine, Lora, Pomona, Grippotyphosa and Hebdomadis). Results: The overall seropositivity of leptospiral antibodies was 9.68% in rodents and shrews, 14.57% in cattle, 10.01% in goats, 31.25% in sheep, and 26.25% in dogs. The seropositivity of Leptospira varied significantly with animal species (OR=1.9, 95 % CI:1.1-3.3, p=0.03). The most frequently detected serovar was Sokoine (27.89%), followed by Pomona (19.47%), Lora (18.26%), Grippotyphosa (17.98%), and Hebdomadis (8.16%), respectively. Conclusion: Our study suggests that further research should be conducted to find out factors of high seropositivity of leptospiral in Unguja. Vaccination of domestic animals with vaccines against local Leptospira strains should be encouraged, and rodent control and public awareness should be emphasized

Seroprevalence of leptospirosis among hospitalized febrile patients in Unguja Island

Background: Leptospirosis is one of the neglected causes of febrile illness and death in developing countries, including Tanzania. The study aims to determine the seroprevalence of leptospirosis among hospitalized febrile patients in Unguja Island.  Methods: A cross-sectional study was carried out in the three selected hospitals in Unguja Island between January and March 2022. A total of 402 participants with febrile illness were enrolled in the study, and blood samples were collected for sera preparation. Microscopic agglutination test (MAT) was used to detect antibodies against five Leptospira serovars, including Sokoine, Lora, Pomona, Grippotyphosa, and Hebdomadis. All sera samples reacted with MAT titers≥1:160 were counted as positive, MAT titers ranging from 1:20 to 1:80 were counted as exposed to Leptospira bacteria while the absence of agglutination was regarded as negative. The data was analyzed using SPSS version 26, 2019. Descriptive and logistic regression was performed, and p≤0.05 was considered statistically significant. Results: The mean age of study participants was 29.62 ±16.34, with a range of 0 days to 80 years. Most of them were females (64.2%) and unemployed (67.9%). The overall seroprevalence of leptospirosis was 7.7% (95% CI: 5.3-10.8). Females were 1.016 times higher likelihood to have leptospirosis (AOR = 1.016, 95% CI: 0.47-2.185, p = 0.968). Participants aged 18-35 were 2.093 times more likely to be infected with leptospirosis (AOR= 2.093, 95% CI: 0.835-5.250, p = 0.115). Participants who were unemployed (AOR = 1.169, 95% CI: 0.522-2.615, p = 0.704) revealed a significantly higher likelihood of being infected with leptospirosis. The predominant Leptospira serovars circulating among febrile patients were Sokoine 44 (10.9%), Lora 25 (6.2%), Grippotyphosa 20 (5.0%), Pomona 10 (2.5%), and Hebdomadis 9 (2.2%). Conclusion: Leptospirosis is a public health threat among febrile patients in Unguja Island; therefore, it’s important to be considered in the differential diagnosis of non-malaria febrile patients for early prevention and control strategies

Leptospira Serovars for Diagnosis of Leptospirosis in Humans and Animals in Africa: Common Leptospira Isolates and Reservoir Hosts

The burden of leptospirosis in humans and animals in Africa is higher than that reported from other parts of the world. However, the disease is not routinely diagnosed in the continent. One of major factors limiting diagnosis is the poor availability of live isolates of locally circulating Leptospira serovars for inclusion in the antigen panel of the gold standard microscopic agglutination test (MAT) for detecting antibodies against leptospirosis. To gain insight in Leptospira serovars and their natural hosts occurring in Tanzania, concomitantly enabling the improvement of the MAT by inclusion of fresh local isolates, a total of 52 Leptospira isolates were obtained from fresh urine and kidney homogenates, collected between 1996 and 2006 from small mammals, cattle and pigs. Isolates were identified by serogrouping, cross agglutination absorption test (CAAT), and molecular typing. Common Leptospira serovars with their respective animal hosts were: Sokoine (cattle and rodents); Kenya (rodents and shrews); Mwogolo (rodents); Lora (rodents); Qunjian (rodent); serogroup Grippotyphosa (cattle); and an unknown serogroup from pigs. Inclusion of local serovars particularly serovar Sokoine in MAT revealed a 10-fold increase in leptospirosis prevalence in Tanzania from 1.9 % to 16.9 % in rodents and 0.26% to 10.75 % in humans. This indicates that local serovars are useful for diagnosis of human and animal leptospirosis in Tanzania and neighbouring countries

Home ranges, sex ratio and recruitment of the multimammate rat (Mastomys natalensis) in semi-arid areas in Tanzania

Investigation of home ranges, sex ratio and recruitment of the multimammate rat (Mastomys natalensis) in semi-arid areas of Tanzania was conducted in maize and fallow fields using the capture-mark-release (CMR) technique. The aim of this study was to generate useful data for the management of M. natalensis. The relative home range size of M. natalensis was significantly higher during the wet [544 m2±25 standard error (SE)] than during the dry (447 m2 ±18 SE) season, in males (521 m2 ±23 SE) than in females (450 m2 ±17 SE) and in adults (576 m2 ±34 SE) than in juveniles (459 m2 ±16 SE). However, there were no significant differences between habitats. Sex ratio was not significantly different (p=0.44) between habitats. Recruitment was significantly higher (p=0.000) in maize fields (mean=0.43) than in fallow land (mean=0.32) and differed significantly over time (p=0.0001) with the highest recruitment recorded from April to July and the lowest from October to December. Management strategies should focus on managing rodents inhabiting maize fields using methods that affect their recruitment in order to reduce the population increase of M. natalensi

The Prevalence of <i>Leptospira</i> Serovars in African Giant Pouched Rats (<i>Cricetomys</i> spp.) from the Ngorongoro Conservation Area, Tanzania

Leptospirosis, also known as Weil’s disease, is a febrile tropical disease of humans and diverse animals. The maintenance hosts of the infectious pathogen, Leptospira spp., are primarily rodents, while other warm-blooded animals and some reptiles are secondary or transient hosts of this pathogen. African giant pouched rats (Cricetomys spp.) have been identified to be important maintenance hosts of pathogenic leptospires in the tropical and subtropical regions of the world. This study assessed the seroprevalence of Leptospira spp. in the African giant pouched rats of the Ngorongoro Conservation Area (NCA), Tanzania, where there is close human, domestic animal, and wildlife interaction. A total of 50 African giant pouched rats were sampled between July 2020 and December 2021. Blood sera were screened for specific leptospiral antibodies using a microscopic agglutination test (MAT), while urine and kidney tissues were examined for the pathogen and pathogen-specific genes using cultures and polymerase chain reactions (PCR), respectively. The pathogen detection varied from 0% in cultures to 6% via the MAT and 20% via PCR. The Fisher exact test was applied to compare positive cases detected through the diagnostic tests, and showed a significant difference in the indirect and direct detection of Leptospira serovars via the MAT and PCR. We conclude that pathogenic Leptospira serovar are found in the NCA and recommend that the NCA authority raises awareness of the existence of the Leptospira serovar in giant African pouched rats, and possibly other rodents. The NCA should initiate appropriate management strategies, including the guided disposal of household garbage, which is the major attractant of rodents to residential areas. Where necessary, the NCA should carry out limited rodent control and periodic monitoring of the pathogen carrier (rodent) populations

Prevalence and Seasonal Variation of <i>Trichuris</i> Worms Infection in <i>Mastomys natalensis</i> in Morogoro and Iringa Regions, Tanzania

Trichuriosis is a disease in mammals caused by the whipworms of the genus Trichuris. These worms are known for the high disease burden they cause in humans and domestic animals, especially in sub-Saharan Africa. In this study, we investigated the prevalence and seasonal variations of Trichuris worms in multimammate rats (Mastomys natalensis). The study was conducted between January and November 2021 in Tanzania, in two regions (Morogoro and Iringa) that differ in their eco-climatic conditions. Removal trapping was conducted using Sherman® live traps during the rainy and dry seasons. The gastrointestinal tracts of captured rodents were screened for the presence of Trichuris worms, which were identified using morphological keys. A total of 200 M. natalensis rats were collected from each of the regions, with 100 animals in each season. For Morogoro, the overall prevalence of Trichuris worms in M. natalensis was 36% (n = 72), of which 42% (n = 42) and 30% (n = 30) were for the rainy and dry seasons, respectively. For Iringa, the overall prevalence was 65% (n = 130), of which there were 80% (n = 80) and 50% (n = 50) for the rainy and dry seasons, respectively. Trichuris worm infections were significantly higher during the rainy season in Iringa than in Morogoro; however, no significant difference in infections between males and females was noted in either region or season. Other helminths detected were Strongyloides spp., Capillaria spp., Hymenolepis spp. and eggs of a helminth that has yet to be confirmed, possibly an Anoplocephalid species. Since M. natalensis is the most important pest species in sub-Saharan Africa, and is a carrier of several zoonotic helminths, there is a need for improved surveillance of helminths infections in the studied regions, in order to establish strategic control programs to reduce their adverse impacts on health

Proportion of prevalence of <i>Leptospira</i> serovars in humans, animals and fish.

<p>Proportion of prevalence of <i>Leptospira</i> serovars in humans, animals and fish.</p

Occurrence, distribution and seroprevalence of local and reference <i>Leptospira</i> serovars in blood collected from humans, domestic and wild mammals and fish in Tanzania (titres ≥ 1:20).

<p>* Leptospirosis prevalence in rodents from study site located 30 km away from <i>Leptospira</i> isolation sites in Tanzania; NA-untested</p><p>Occurrence, distribution and seroprevalence of local and reference <i>Leptospira</i> serovars in blood collected from humans, domestic and wild mammals and fish in Tanzania (titres ≥ 1:20).</p

<i>Leptospira</i> isolation rate in different animal species in Tanzania.

<p><i>Leptospira</i> isolation rate in different animal species in Tanzania.</p