Diversity of rodent-borne zoonotic pathogens at the human-animal-environment interface in Qatar.
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Date
2021
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Abstract
Rodents are the most diversified terrestrial mammals in the world. These animals assist with
maintaining a healthy ecosystem through the soil structure modification, aeration, and hydration,
although 5-10% are regarded as pests and carry zoonotic pathogens. Besides consumption and damage
of our food and property, they are responsible for the transmission of several diseases, including plague,
typhus, and leishmaniasis. Commensal rodents are the primary source of these pathogens because of
their close proximity to humans. Qatar is a small country in the Arabian Peninsula. Four rodent species
have been recorded in this country, that includes three commensal (Mus musculus, Rattus norvegicus,
and Rattus rattus) and one wild (Jaculus jaculus) species. The zoonotic importance of rodents is yet to
be explored. Knowing the pathogens originating from rodents is essential for early preparedness,
prevention, and control. Therefore, the current study was undertaken on commensal rodents, rodentborne
zoonotic pathogens, and the factors that are associated with pathogen prevalence among rodents,
such as rodent sex, age, and trapping location in Qatar. A cross-sectional study was conducted between
August 2019 and February 2020, which trapped rodents from different facilities, such as livestock and
agricultural farms, bachelor and family accommodations, and industrial and commercial areas of Qatar.
After studying the morphological and morphometric characters, blood samples, ectoparasites and
visceral samples were collected from the captured rodents. Parasitic, bacterial, and viral pathogens were
identified and characterized using gross, necropsy, microscopic, culture, biochemical, immunologic,
and molecular methods. Descriptive statistics and univariate analysis were conducted to detect rodents,
rodent-borne pathogens abundance, and the related risk factors. The study trapped 148 rodents, most of
which were adults (n = 138, 93.2%, 95% CI: 87.92–96.71), and from livestock farms (n = 79, 49%,
95% CI: 41.02–57.65). R. norvregicus was the most prevalent (n = 120, 81%, 95% CI: 73.83–87.05),
followed by R. rattus (n=24, 16%, 95% CI:10.68–23.16) and M. musculus (n=4, 3%, 95% CI: 0.74–
6.78) with an average body weight of 18.8 ± 2.2 gm, 264.3 ± 87.5 gm, and 130 ± 71.3 gm, respectively.
This is the first morphologic and morphometric study of commensal rodents in Qatar and the Arabian
Peninsula that detected the Qatari rodents are relatively smaller than those of Turkey, Tunisia, and Iran.
About 63.5% of the rodents were infected with at least one of the 9 species of parasites, viz. Xenopsylla
astia, Ornithonyssus bacoti, Hymenolepis diminuta, Taenia taeniaeformis, Capillaria annulosa,
Strongyloides spp., Giardia spp., Toxoplasma gondii, Trypanosoma lewisi, and Leishmania spp.
Helminths were the most prevalent (46.0%), followed by ectoparasites (31.8%) and protozoa (29.1%).
Going by individual species prevalence, X. astia ranked the highest (31.8%), where the lowest prevalent
parasite was C. annulosa (0.7%). The prevalence of H. diminuta was positively correlated (OR=4.13;
p = 0.00) with the prevalence of X. astia. The study also identified thirteen bacterial species, namely
Acinetobacter baumannii, Aeromonas salmonicida, Citrobacter freundii, Citrobacter koseri,
Enterobacter aerogenes, Enterobacter cloacae, Escherichia coli, Hafnia alvei, Klebsiella pneumoniae,
Providencia stuartii, Proteus mirabilis, Pseudomonas aeruginosa, and Salmonella enterica, from the
intestine samples. The majority of the bacteria were E. coli (54.63%, 95% CI: 44.76-64.24), followed
by P. mirabilis (17.59%, 95% CI: 10.94-26.10), and K. pneumoniae (8.33%, 95% CI: 3.88-15.23). The
study detected 31.58% (6/19, 95% CI: 12.58-56.55) of the flea pools, and one (1/1) mite pool was
positive with Rickettsia spp. S. enterica showed the highest antimicrobial resistance (100% resistant to
8 antimicrobials). The top resistant antimicrobials were from cephalosporin, followed by penicillin and
tetracycline groups. E. coli (26.92%, 95% CI:11.57-47.97) and K. pneumonia (50%, 95% CI: 6.76-
93.24) were ESBL (extended-spectrum beta-lactamases) producers. The studied rodents are indicators
of the presence and dispersal of zoonotic pathogens in Qatar. Urgent action is needed to prevent future
spillover of these pathogens at the human-animal-environment interface. It is essential to understand
the biology, epidemiology, and transmission dynamics of these pathogens. Farm biosecurity and
integrated pest management approach should be implemented in the farm premises. Implementing the
One Health approach to combat rodent-borne zoonoses in order to reduce the risk of the future epidemic
in Qatar is strongly recommended.
Description
Doctoral Degree. University of KwaZulu-Natal, Durban.