Isolation, Identification and Associated Risk Factors of Non‐Tuberculous Mycobacteria Infection in Humans and Dromedary Camels in Samburu County, Kenya
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Date
2020
Authors
Asaava, Lucas L. A.
Githui, Willie A.
Mwangi, Moses
Mwangi, Edwin
Juma, Ernest
Moraa, Ruth
Halakhe, Adan
Gicheru, Michael M.
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
Non‐tuberculous mycobacteria are of public health significance, and zoonotic infection is attributed to the sociocultural practice of consumption of raw milk and the close human–livestock contact in pastoral communities. This study aimed at isolation, identification of mycobacteria from human sputum and camel milk and risk factors assessment in Samburu East, Kenya. Six hundred and twelve camels and 48 people presumed to have tuberculosis (TB) from 86 households in Wamba and Waso regions were screened. Camels were categorized into Somali, Turkana and Rendile breeds. Single intradermal comparative tuberculin test (SICTT) was used as a herd‐screening test on lactating camels and a milk sample collected from reactive camels. Sputum samples were collected from eligible members of participating households. A standard questionnaire on possible risk factors for both humans and camels was administered to respective household heads or their representatives. Total camel skin test reactors were 238/612 (38.9%). Milk and sputum samples were analysed at KEMRI/TB research laboratory for microscopy, GeneXpert®, culture and identification. Isolates were identified using 16S rRNA gene sequencing at Inqaba biotec in South Africa. Sixty‐four isolates were acid‐fast bacilli (AFB) positive of which M. fortuitum (3), M. szulgai (20), M. monacense (5), M. lehmanni (4), M. litorale (4), M. elephantis (3), M. duvalii (3), M. brasiliensis (1), M. arcueilense (1) and M. lentiflavum (1) were from milk; M. fortuitum (1), M. szulgai (2) and M. litorale (1) were from humans. Risk factors included the following: Turkana breed (OR = 3.4; 95% CI: 1.2–9.3), replacements from outside the County (OR = 2.1; 95% CI: 0.3–12.3), presence of other domestic species (small stock; OR = 4.6) and replacement from within the herd (OR = 3.2; 95% CI: 0.7–14.7). Zoonotic risk practices included raw milk consumption, shared housing and handling camels. Monitoring of zoonotic NTM through surveillance and notification systems is required.
Description
This work was supported by the National Research Fund (NRF), Kenya [grant number NACOSTI/RCD/ST&I/7THCALL/PHD/258] and support in kind from ongoing projects at the KEMRI‐CRDR laboratory. The funding body was not involved in study design; collection, analysis, and interpretation of data; report writing; and in the decision to submit this article for publication.
Keywords
Dromedary camel, Epidemiology, Milk, Non‐tuberculous mycobacteria, Zoonosis, Kenya
Citation
Asaava, L. L., Githui, W. A., Mwangi, M., Mwangi, E., Juma, E., Moraa, R., ... & Gicheru, M. M. (2020). Isolation, identification and associated risk factors of non‐tuberculous mycobacteria infection in humans and dromedary camels in Samburu County, Kenya. Zoonoses and Public Health, 67(6), 713-731.