Survey for selected pathogens in wild pigs (Sus scrofa) from Guam, Marianna Islands, USA

Authors: CLEVELAND, CHRISTOPHER - Southeastern Cooperative Wildlife Disease Study; DENICOLA, ANTHONY - White Buffalo, Inc; Dubey, Jitender; Hill, Dolores; BERGJAUS, ROY - University Of Georgia; YABSLEY, MICHAEL - Southeastern Cooperative Wildlife Disease Study

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2017
Publication Date: 6/1/2017
Citation: Cleveland, C., Denicola, A., Dubey, J.P., Hill, D.E., Bergjaus, R.D., Yabsley, M. 2017. Survey for selected pathogens in wild pigs (Sus scrofa) from Guam, Marianna Islands, USA. Veterinary Microbiology. 205:22-25.

Interpretive Summary: Food safety is a major public health concern worldwide. Humans can acquire several diseases after the ingestion of undercooked/uncooked pork. Toxoplasmosis, sarcocystosis and trichinellosis are some of the parasitic diseases that are acquired through eating infected pork. The island of Guam is an unincorporated territory of the United States located in the Marianna Island chain. In the present study, the authors surveyed samples from 47 pigs trapped/hunted in Gaum for several pathogens. Antibodies to Toxoplasma gondii were found in 11% of pigs. Travelers to this island should be aware of dangers of eating undercooked meat. The results will be of interest to biologists, zoo veterinarians, and parasitologists, and help diagnosis of sarcocystosis.

Technical Abstract: Pigs (Sus scrofa) were introduced to the United States Territory of Guam in the late 1600’s and are now feral, widespread and present in high densities on parts of the island. Feral pigs are reservoirs for pathogens of concern to domestic animals and humans. Although there are no data on pathogen exposure of wild pigs on Guam, exposure to porcine parvovirus, transmissible gastroenteritis, and Leptospira interrogans has been documented in domestic swine. The close proximity of humans, domestic animals, and wild pigs on Guam, combined with the liberal hunting regulations of wild pigs, results in frequent opportunities for pathogen transmission. From February-March 2015, blood, tissue and ectoparasite samples were collected from 47 wild pigs. Serologic testing found exposure to numerous pathogens including Brucella spp. (2%), Toxoplasma gondii (11%), porcine reproductive and respiratory syndrome (PRRS) virus (13%), porcine circovirus type 2 (36%), pseudorabies virus (64%), Actinobacillus pleuropneumoniae (93%), Lawsonia intracellularis (93%), and porcine parvovirus (94%). Eleven (24%) samples had low titers (1:100) to Leptospira interrogans serovars Bratislava (n=6), Icterohaemorrhagiae (n=6), Pomona (n=2), and Hardjo (n=1). Kidney samples from nine pigs with Leptospira antibodies were negative for Leptospira antigens by immunohistochemistry. Few gross lesions were noted but numerous pigs had Metastrongylus lungworms, three had Stephanurus dentatus, and one had a liver abscess with intralesional nematode larvae. Lice (Hematopinus suis) and ticks (Amblyomma breviscutatum) were found on 12 and seven pigs, respectively. We did not detect antibodies to Influenza A viruses in any pigs. In contrast to the previous survey of domestic swine, we found evidence of numerous pathogens in wild pigs including new reports of pseudorabies virus, PRRS virus, Brucella, and Leptospira in pigs on Guam. These findings highlight that domestic swine-wild pig interactions should be prevented and precautions are needed when handling wild pigs to minimize the risk of pathogen transmission.