Seroprevalence of leptospira among rodents and shrews in public markets and hospitalized febrile patients in Unguja Island

Loading...
Thumbnail Image

Date

2023-05

Journal Title

Journal ISSN

Volume Title

Publisher

Sokoine University of Agriculture

Abstract

Leptospirosis is a neglected infectious zoonotic disease of public health significance caused by spirochete pathogenic bacteria of the genus Leptospira. This disease occurs mainly in tropical and subtropical countries and affects animals and humans, of which rodents and shrews are considered significant reservoirs of infection. Human might be infected by Leptospira pathogen through a contact mode of transmission, either direct or indirect, with the urine of infected animal’s host or a urine-polluted environment such as water or soil. However, infected humans develop a range of symptoms undifferentiated from other tropical diseases, such as malaria, particularly in regions with high malaria prevalence. A cross-sectional study was carried out between January and April 2022 in Unguja Island (i) to determine the seroprevalence of Leptospira infection among rodents and shrews in public markets and (ii) to determine the seroprevalence of leptospirosis among hospitalized febrile patients. Blood samples were collected from 210 live captured rodents and shrews in the five purposively selected markets including Darajani, Mombasa, Jumbi, Kwerekwe C and Mkokotoni. Likewise, 402 human blood samples were collected from febrile patients who were attended to the selected hospitals namely Mnazi Mmoja referral hospital, Kivunge district hospital and Makunduchi district hospital. The Leptospira antibodies of rodents, shrews and humans were tested against five serovars namely Sokoine, Lora, Pomona, Grippotyphosa and Hebdomadis using the Microscopic Agglutination Test (MAT). The results indicated that out of 210 rodents and shrews captured in public markets, 16 were seropositive for Leptospira serovars. Thus, the overall seroprevalence of Leptospira infection was 7.6% (95% CI =4.4−12.1), with a prevalence of 6.6% (14/210) in rodents and 1.0% (2/210) in shrews. The Leptospira serovars circulating among rodents and shrews antibodies were Sokoine 11 (5.2%), Lora 4 (1.9%), Pomona 2 (1.0%), and Grippotyphosa 1 (0.5%). Rattus rattus were shown to have high seroprevalence of Leptospira infection (4.2%), followed by Rattus norvegicus (1.4%), Mus spp (1.0%) and Crocidura spp (1.0%). Furthermore, out of 402 human sera collected from three hospitals, 31 human samples were seropositive for Leptospira serovars, and thus, the overall seroprevalence of human leptospirosis was 7.7% (95% CI = 5.3−10.8). Females 20 (5.0%) were shown to have high seroprevalence of disease compared to males 11 (2.7%). The major Leptospira serovars circulating in humans were Sokoine 44 (10.9%), Lora 25 (6.2%), Grippotyphosa 20 (5.0%), Pomona 10 (2.5%), and Hebdomadis 9 (2.2%). The findings of this study have indicated that several Leptospira serovars are common to rodents, shrews and humans. Likewise, market features and practices, including a poor drainage system, the presence of stagnant water, unhygienic conditions, and wet soil, favor rodent population and pose a risk of environmental contamination and perpetuation rodent-environment-human infection cycle. This report call for consideration and inclusion of this disease in the differential diagnosis of acute febrile syndromes in humans.

Description

Dissertation

Keywords

Seroprevalence, Leptospirosis, rodents and shrews, febrile patients, Unguja Island

Citation