Open Access
Research (Published online: 25-07-2021)
26. Coinfection of Chlamydia spp. and herpesvirus in juvenile farmed Siamese crocodiles (Crocodylus siamensis) in Thailand
Weena Paungpin, Metawee Thongdee, Somjit Chaiwattanarungruengpaisan, Ladawan Sariya, Wanna Sirimanapong, Tanit Kasantikul, Rassameepen Phonarknguen, Poonnut Darakamas and Nlin Arya
Veterinary World, 14(7): 1908-1914

Weena Paungpin: The Monitoring and Surveillance Center for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand.
Metawee Thongdee: The Monitoring and Surveillance Center for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand.
Somjit Chaiwattanarungruengpaisan: The Monitoring and Surveillance Center for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand.
Ladawan Sariya: The Monitoring and Surveillance Center for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand.
Wanna Sirimanapong: The Veterinary Aquatic Animal Research Health Care Unit, Department of Clinical Sciences and Public Health, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand.
Tanit Kasantikul: Department of Pre-clinic and Applied animal Science, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand; Veterinary Diagnostic Laboratory, Clemson Livestock Poultry Health, 500 Clemson Rd, Columbia, SC 29229, USA.
Rassameepen Phonarknguen: The Monitoring and Surveillance Center for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand.
Poonnut Darakamas: Prasu-Arthorn Animal Hospital, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand.
Nlin Arya: Department of Pre-clinic and Applied animal Science, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand.

doi: www.doi.org/10.14202/vetworld.2021.1908-1914

Share this article on [Facebook] [LinkedIn]

Article history: Received: 10-03-2021, Accepted: 15-06-2021, Published online: 25-07-2021

Corresponding author: Nlin Arya

E-mail: nlin.ary@mahidol.edu

Citation: Paungpin W, Thongdee M, Chaiwattanarungruengpaisan S, Sariya L, Sirimanapong W, Kasantikul T, Phonarknguen R, Darakamas P, Arya N (2021) Coinfection of Chlamydia spp. and herpesvirus in juvenile farmed Siamese crocodiles (Crocodylus siamensis) in Thailand, Veterinary World, 14(7): 1908-1914.
Abstract

Background and Aim: For a decade, chlamydial and herpesvirus infections have caused significant morbidity and mortality in farmed crocodiles. In September 2017, a total of 160 juvenile freshwater Siamese crocodiles (Crocodylus siamensis) with conjunctivitis/pharyngitis lesions were admitted at the Veterinary Aquatic Animal Research Health Care Unit, Faculty of Veterinary Science, Mahidol University. All crocodiles did not respond well to antibiotics or supportive treatments and died. This study aimed to detect and identify the causative agents associated with conjunctivitis/pharyngitis and fatal outcomes in juvenile farmed Siamese crocodiles.

Materials and Methods: A total of 138 pharyngeal and conjunctival swabs and conjunctival scrapes were collected from live crocodiles. All swab and scrape samples were DNA-extracted and amplified by polymerase chain reaction (PCR) using Chlamydiaceae- and herpesvirus-specific primers. Tissue samples (brain, lung, liver, heart, spleen, and intestine) were collected from two representative postmortem animals. All tissue samples were processed for molecular and pathological analyses.

Results: PCR examinations identified chlamydial and herpesvirus DNA in 92% (126/138) and 100% (138/138), respectively, of the tested swab and scrape samples. Of those positive samples, 79% (26/33), 67% (4/6), and 98% (97/99) of the pharyngeal swabs, conjunctival swabs, and conjunctival scrapes, respectively, were positive for both chlamydial and herpesvirus DNA. Histopathological examination indicated necrosis and mononuclear cell infiltration in the liver, kidney, and intestine of the affected animals. The intracytoplasmic accumulation of Chlamydia was randomly observed in the examined tissue sample. Moreover, the presence of chlamydial and herpesvirus DNA was also detected in the tissue samples, including the heart, intestine, brain, lung, liver, and spleen, of the affected animals by PCR. Phylogenetic analyses revealed that Chlamydia spp. detected in the juvenile Siamese crocodiles was notably different from other known species in the Chlamydia genus, while the herpesvirus detected in the crocodiles was closely related to crocodyline herpesvirus 1.

Conclusion: Based on histopathological and molecular examinations, this report provided the first evidence of coinfection of Chlamydia spp. and crocodyline herpesvirus 1 in juvenile Siamese crocodiles in Thailand.

Keywords: Chlamydia spp., herpesvirus, juvenile, pathology, phylogeny, Siamese crocodile.