Background: Leptospirosis is among the major neglected zoonoses in developing countries. The prevalence of leptospirosis remains underestimated in many African countries because of limited diagnostic facilities. We studied Leptospira seropositivity prevalence in humans, sheep, goats and rodents in a semi-arid region of central Tanzania and compared findings with reports from humid tropical areas. The aims were to establish the disease burden in different settings; understand circulating Leptospira serovars and potential major reservoirs for establishing appropriate control measures. Methods: Humans, sheep, goats, rodents and shrews (insectivores) were sampled from Bahi district, a semi-arid area in central Tanzania. Samples were tested for leptospiral antibodies using microscopic agglutination test (MAT) consisting of Leptospira serovars mainly reported in Tanzania and reference strains. Findings were compared with previous data to determine the disease epidemiological patterns. Results and conclusion: Semi-arid area showed high Leptospira seropositivity prevalence in humans and domestic animals due to intensive human–animal interactions at scarce water points and by flash flooding which occur in the area. Rodent population in the semi-arid areas was relatively low due to flooding. Leptospira seropositivity in rodents was also slightly lower, and the rodents appeared to be prolific breeders, probably as a means to compensate for the lost population during extreme drought as well as during short spells of floods. Intensive human–animal interaction in the semi-arid areas especially, in water sources in valleys where human and animals often meet, likely increased the risk of leptospirosis transmission to rice farmers in the area. Goats and sheep which are kept around homesteads had higher leptospiral antibodies prevalence (62%), nearly double of the 38% reported in same species in humid tropical regions of Tanzania. Livestock, especially goats and sheep, could be the major source of leptospirosis transmission to humans. Vaccination of livestock with vaccines against local Leptospira strains should be encouraged, and rodent control emphasized, as part of a management strategy against leptospirosis. Public awareness of leptospirosis must also be raised and supported by availability of rapid test kits in clinics for preliminary testing of leptospirosis in people with fevers of unknown origin.

Trained African giant pouched rats (Cricetomys gambianus) can detect Mycobacterium tuberculosis (Mtb) in sputum samples from humans with confirmed pulmonary tuberculosis (TB).¹ x 1 Weetjens, B.J., Mgode, G.F., Machang’u, R.S., Kazwala, R., Mfinanga, G., Lwilla, F., Cox, C., Jubitana, M., Kanyagha, H., Mtandu, R., Kahwa, A., Mwessongo, J., Makingi, G., Mfaume, S., Van Steenberge, J., Beyene, N.W., Billet, M., and Verhagen, R. African pouched rats for the detection of pulmonary tuberculosis in sputum samples. Int J Tuberc Lung Dis. 2009; 13: 1–7 PubMed | Google Scholar See all References These rats target volatile compounds (odours) specific to Mtb, the causative agent of TB. Mtb and nontuberculous mycobacteria (NTM) species belong to the genus Mycobacterium, which is related to the genus Nocardia and Rhodococcus. Some NTM and members of the genera Nocardia and Rhodococcus, which are also acid-fast bacilli, are increasingly recognized as pathogens of the respiratory tract² x 2 Prescott, J.F. Rhodococcus equi: an animal and human pathogen. Clin Microbiol Rev. 1991; 4: 20–34 PubMed | Google Scholar See all References ^{, 3} x 3 De La Iglesia, P., Viejo, G., Gomez, B., De Miguel, D., Del Valle, A., and Otero, L. Fatal pulmonary Nocardia farcinica infection. J Clin Microbiol. 2002; 40: 1098–1099 Crossref | PubMed | Scopus (22) | Google Scholar See all References ^{, 4} x 4 Wadhwa, V., Rai, S., Kharbanda, P., Kabra, S., Gur, R., and Sharma, V.K. A fatal pulmonary infection by Nocardia brasiliensis. Indian J Med Microbiol. 2006; 24: 63–64 Crossref | PubMed | Scopus (8) | Google Scholar See all References and can be misdiagnosed as Mtb in smear microscopy during TB diagnosis. Misdiagnosis of pulmonary nocardiosis and/or Rhodococcus infection as TB may lead to unnecessary treatment with anti-TB drugs.

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.

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 ET FACTEURS LIES A LA LEPTOSPIROSE BOVINE DANS DES PETITES EXPLOITATIONS DE FERMES LAITIERES DANS LA REGION DE TANGA EN TANZANIE Résumé Des prélèvements de sérum à des bovins laitiers croisés (n = 230) issus de 120 fermes choisies au hasard dans la région de Tanga ont été testés en vue de déterminer la présence des anticorps contre les leptospires pendant la période janvier - avril 1999. Les prélèvements de sérum étaient examinés à l\'aide d\'un test d\'agglutination microscopique (TAM) contre 5 sérovars de Leptospira interrogans. Vingt-et-une (21) des 120 fermes 17,5% [ Intervalle de confiance (IC) 95% = 11,2 ; 25,3)] avaient au moins un animal positif pour un ou deux sérotypes de leptospire et 10,8% [ IC 95% = 7,15 ; 15,62] des animaux examinés étaient positifs pour la leptospirose. Les anticorps les plus fréquents détectés étaient ceux contre les antigènes de sérovars Tarassovi (44%), Hardjo (32%), Pomona (12%), Bataviae (8%) et Grippotyphosa (4%). En utilisant des modèles à effet mixte (avec une ferme comme facteur aléatoire), l\'animal dans le district de Lushoto et la race zébu étaient liés à la baisse de risque de séropositivité [ratio de probabilité (RP) = 0,12 ; P = 0,050 pour l\'animal de Lushoto et RP = 0,31 ; P = 0,019 pour la race zébu, respectivement]. En revanche, la race Boran était identifiée comme étant un facteur de risque à la leptospirose (RP = 2,7 ; P = 0,050). La séroprévalence est probablement due à une exposition aux leptospires par le passé ou à l\'infection asymptomatique par la leptospirose parce que l\'on n\'a pas effectué de vaccination contre la leptospirose dans la région de Tanga. Mots-clés : Leptospirose, épidémiologie, séroprévalence, facteurs de risque, petite exploitation, bétail laitier, Tanga, Tanzanie. Summary Cross-bred dairy cattle serum samples (n =230) from 120 hundred randomly selected farms in the Tanga region were tested for the presence of leptospira antibodies during the period January to April 1999. Serum samples were screened using microscopic agglutination test (MAT) against 5 serovars of Leptospira interrogans. Twenty-one (17.5%, 95% Confidence interval [CI] = 11.2, 25.3) of the farms had at least one individual animal positive for one or two of the leptospira serotype and 10.8 %( 95%CI = 7.15, 15.62) of the animals were positive for leptospirosis. The most common antibodies detected were those against antigens of serovars Tarassovi (44%), Hardjo (32%), Pomona (12%), Bataviae (8%) and Grippotyphosa (4%). Using mixed-effect models (with farm as a random effect), animal located in Lushoto district and Zebu breed were associated with decreased risk of seropositivity (Odd ratio [OR] = 0.12, P = 0.050 for Lushoto and OR = 0.31, P = 0.019 for Zebu, respectively). Boran breed was identified as a risk factor to leptospirosis (OR = 2.7, P = 0.050). The seroprevalence probably reflects a past exposure to leptospiral organisms or asymptomatic leptospirosis infection because vaccination against leptosprosis has not been practiced in Tanga region. Keywords: Leptospirosis, epidemiology, seroprevalence, risk factors, smallholder, dairy cattle, Tanga, Tanzania Bull Anim. Hlth. Prod. Afr. (2004) 53, 51-59