Coxiella burnetii is a highly transmissible intracellular bacterium with a low infective dose that causes Q fever (coxiellosis), a notifiable zoonotic disease distributed worldwide. Livestock are the main source of C. burnetii transmission to humans, which occurs mostly through the aerogenous route. Although C. burnetii is a major abortifacient in small ruminants, it is less frequently diagnosed in aborting cattle. We report a case of C. burnetii abortion in a lactating Holstein cow from a dairy farm producing and selling artisanal cheese directly to consumers in Uruguay, and review the literature on coxiellosis as a bovine abortifacient in South America and as a milk-borne disease. The aborted cow had severe necrotizing placentitis with abundant intratrophoblastic and intralesional C. burnetii confirmed by immunohistochemistry and PCR. After primo-infection in cattle, C. burnetii remains latent in the lymph nodes and mammary glands, with milk being a significant and persistent excretion route. Viable C. burnetii has been found in unpasteurized milk and cheeses after several months of maturing. The risk of coxiellosis after the consumption of unpasteurized dairy products, including cheese, is not negligible. This report raises awareness on bovine coxiellosis as a potential food safety problem in on-farm raw cheese manufacturing and sales. The scant publications on abortive coxiellosis in cattle in South America suggest that the condition has probably gone underreported in all countries of this subcontinent except for Uruguay. Therefore, we also discuss the diagnostic criteria for laboratory-based confirmation of C. burnetii abortion in ruminants as a guideline for veterinary diagnosticians.
|Journal||Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]|
|Early online date||17 Aug 2021|
|Publication status||E-pub ahead of print - 17 Aug 2021|
Bibliographical noteFunding Information:
This work was partially funded by grants FSSA_X_2014_1_105696 of the Uruguayan “Agencia Nacional de Investigación e Innovación” (ANII) and PL_027 N-23398 from the “Instituto Nacional de Investigación Agropecuaria” (INIA). The first author received a graduate scholarship POS_EXT_2015_1_123804 from ANII.
© 2021, Sociedade Brasileira de Microbiologia.