Yersinia pseudotuberculosis in a Closed Colony of Egyptian Fruit Bats (Rousettus aegyptiacus)

Abstract

An outbreak of Yersinia pseudotuberculosis (Yptb) occurred in a closed colony of Egyptian fruit bats (Rousettus aegyptiacus) and resulted in the death of seven bats over a 6-week period. An initial survey of the remaining bats revealed visceral abscessation characteristic of pseudotuberculosis in five of the 12 bats examined (41.7%), inciting depopulation of the colony. At necropsy, 70% of the 115 bats in the colony exhibited gross evidence suggestive of Yptb infection, including mesenteric lymphadenopathy (ML), hepatic abscessation (HA), and/or splenomegaly (SPM). Thirty of these bats (13 females and 17 males of various ages) were chosen at random and their tissues submitted for bacterial culture and histopathologic examination. Twenty-three of these 30 bats had one or more gross lesions considered consistent with Yptb, including ML, HA, and SPM. On histopathology, four of the 30 bats had necrotizing lesions containing Gram-negative bacteria in multiple organs, while 18 others exhibited mild mesenteric lymphadenitis and hepatitis. Four of the 30 bats had positive cultures for Yptb. Bats with gross evidence of mesenteric lymphadenopathy, splenomegaly, or histopathologic presence of demodicosis or bacteria in tissues were more likely (P < 0.05) to have a positive Yersinia culture. Examination of the correlation between population density and mortality rates of the colony revealed that the mortality rate of subadult bats increased dramatically at the time of the outbreak, when the population density was at its highest. It is suspected that stress, primarily from severe overcrowding, predisposed the bat colony to morbidity and mortality from this organism, which likely originated from a rodent reservoir.

Bats and Bacterial Pathogens: A Review

“…As diagnostic investigations in bats are markedly impaired by fast decomposition of dead animals, the importance of pathogenic Yersinia species might be underestimated, especially in hibernating bats. Outbreaks of Y. pseudotuberculosis infection have occasionally been observed in closed colonies of captive flying foxes (Williams, 2004; Child‐Sanford et al., 2009), which supports the pathogenic potential of Y. pseudotuberculosis strains for bats.…”

Genomic insights into a sustained national outbreak of Yersinia pseudotuberculosis

“…It is capable of infecting both human and animal hosts, and has a broad range of domestic and wild animal reservoirs (Fukushima and Gomyoda 1991; Childs-Sanford et al 2009; Magistrali et al 2014; Chakraborty et al 2015). Transmission is by the fecal-oral route, and human infection can occur by the ingestion of contaminated produce or water, or alternatively by direct contact with an infected animal or human (Toma 1986; Fukushima et al 1989; Jalava et al 2004; Vincent et al 2008; Rimhanen-Finne et al 2009).…”

YersiniaSpecies Isolated from Bats, Germany

“…Y. pseudotuberculosis and Y. enterocolitica are frequently isolated from a variety of wild and domestic animals ( 5 ), but little is known about the occurrence of yersiniosis in free-ranging chiropteran species. Only few reports of fatal Y. pseudotuberculosis infection in captive flying foxes have been published ( 6 , 7 ). In Europe, Y. pseudotuberculosis strains belonging to serogroup 1 are most common and cause most Y. pseudotuberculosis infections in humans and animals ( 5 ).…”