Lymphoid Follicular Cloacal Inflammation Associated with a Novel Herpesvirus in Juvenile Alligators (Alligator Mississippiensis)

Abstract

Abstract. Multifocal hyperemic nodules and plaques associated with the cloacal mucosa of juvenile alligators (Alligator mississippiensis) at a public aquarium were investigated. Grossly, pale pink to dark red multifocal, circular lesions of varying degrees of severity were identified on the cloacal and, in males, phallus mucosa. Cloacal mucosa biopsies were obtained from 2 of the alligators. These samples were examined histologically and by polymerase chain reaction (PCR) using consensus primers targeting a conserved region of the herpesvirus polymerase gene. Microscopically, the lesions were characterized as submucosal lymphoid follicles with hyperemia and hemorrhage. No inclusion bodies were observed. Minimal to no anisokaryosis was present, and no etiologic agents were identified. Through PCR, a band consistent in size with herpesvirus was observed. Tissues showing similar clinical, histopathologic, and PCR findings were collected from animals at an alligator farm several months later. Sequencing of the PCR amplicon resulted in a 180-base pair sequence that shared 85% sequence identity with tortoise herpesvirus-1.Key words: Alligator mississipiensis; alphaherpesvirus; cloaca; crocodilian; petechiation; reptile.Herpesviruses are enveloped double-stranded DNA viruses measuring 120-200 nm in diameter. They are known to affect many species of mammals, birds, reptiles, amphibians, fish, and invertebrates. Transmission is believed to occur through mucosal contact and less commonly through the aerosolization of infectious droplets. Once acquired, virus persists in nerve or lymph tissue and spreads through continuous or intermittent shedding, which is associated with stress caused by other infections, shipping, cold, or crowding. Infected animals generally show symptoms associated with the respiratory or reproductive tract or the central nervous system. Herpesviruses have also been known to cause epithelial tumors, cell lysis, and in some cases no clinical symptoms. Intranuclear inclusion bodies are often observed on histopathology and in cell cultures. 12 In reptiles, herpesvirus infections have been reported in snakes, chelonians, and lizards. In crocodilians, there is 1 report of herpesviruslike particles being observed. 8 In October 2003, routine annual physical examinations were performed on 15 (4 males, 11 females) 4-to 5-yearold, juvenile alligators housed at a North Carolina aquarium. These animals weighed 3-9 kg and were 94-135 cm in length. They had been obtained in March of 2002 from an alligator farm in Florida and had never been observed exhibiting reproductive behaviors. All 15 alligators were housed together in a 12.19-ϫ 2.44-m enclosure containing a 45,425-liter pool with a maximum depth of 2.14 m. They shared this enclosure with a few aquatic turtles and were fed chicken and beef twice weekly.All 15 alligators were manually restrained for physical examination, which included observation of the eyes, ears, and skin, abdominal and appendage palpation, and manual sexing. Blood was collected from the occ...

Viruses Infecting Reptiles

“…In reptiles, HVs have been detected in lizards [41–48], snakes [49,50], chelonians [51–63] and crocodylians [64,65]. None of the reptilian HVs has yet been assigned to a specific genus in the family Herpesviridae .…”

Diagnostic investigation of new disease syndromes in farmed Australian saltwater crocodiles (Crocodylus porosus) reveals associations with herpesviral infection

“…25 There is also a report associating cloacal lymphoid nodules in juvenile farmed American alligators (Alligator mississippiensis) with herpesvirus infection. 11 However, the herpesvirus was subsequently determined to have likely been a contaminant (GenBank accession AY913769.1).…”

Molecular identification of three novel herpesviruses found in Australian farmed saltwater crocodiles (Crocodylus porosus) and Australian captive freshwater crocodiles (Crocodylus johnstoni)

“…In the previous work by Govett et al (2005), a new crocodilian herpesvirus was announced and tentatively named Crocodylid herpesvirus 1 but, as mentioned above, the 100% sequence homology with a tortoise herpesvirus suggests that this finding appears to be an error. There is precedent set for use of host genus rather than family name when naming herpesviruses; several primate viruses infecting the genus Macaca have been renamed as Macacine herpesvirus.…”

“…There is precedent set for use of host genus rather than family name when naming herpesviruses; several primate viruses infecting the genus Macaca have been renamed as Macacine herpesvirus. To help prevent confusion between the herpesviruses in our paper and the one described by Govett et al (2005), we propose use of the genus (crocodyline), instead of family (crocodylid), in naming these viruses. Should a herpesvirus emerge with strong evidence that its host is an alligator, we would suggest that the name Alligatorine herpesvirus be considered (after its genus).…”

“…In the first, herpesvirus-like particles were seen in degenerate superficial epidermal cells in a six-month old saltwater crocodile (Crocodylus porosus) that had been farm-hatched in the Northern Territory of Australia and then transported to a facility in Victoria, Australia for stress research (McCowan et al, 2004). In the second investigation, a novel herpesvirus, named Crocodylid herpesvirus 1, was reportedly detected by sequencing of a PCR product from cloacal lesions of juvenile alligators (Alligator mississippiensis) from two alligator farms in the USA (Govett et al, 2005). However, since publication, sequence 100% homologous to this was found in several Greek (Testudo.…”