PROTOZOAN PARASITES AFFECTING FOOD ANIMALS, FOOD SAFETY, AND PUBLIC HEALTH
Title: Detection of Assemblage A, Giardia duodenalis and Eimeria spp. in Alpacas on Two Maryland Farms
Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 9, 2008
Publication Date: May 31, 2008
Citation: Trout, J.M., Santin, M., Fayer, R. 2008. Detection of Assemblage A, Giardia duodenalis and Eimeria spp. in Alpacas on Two Maryland Farms. Veterinary Parasitology. 153:203-208.
Interpretive Summary: Despite the widespread importance of the domesticated camelids, alpacas and llamas in South America, and the increasing use of alpacas as fiber animals in North America, there are relatively few reports on the prevalence of economically important protozoan parasites in these animals. Alpacas are ruminants with digestive systems similar to cattle. Thus parasites common to cattle such as Giardia, Cryptosporidium and Eimeria could be prevalent in alpacas as well. This information is especially important for Cryptosporidium and Giardia as many livestock species carry types of these parasites that are infectious for humans. This study used a combination of microscopy and DNA analysis techniques to identify parasites present in alpacas on two farms in Maryland. Cryptosporidium was not detected on either farm, however the farms had no animals less than 10 weeks of age, and Cryptosporidium is typically more prevalent in very young animals. A type of Giardia that is infectious for both humans and cattle was detected in a few animals on both farms and thus alpacas should be regarded as a potential source of Giardia infecting humans and cattle.
Sixty one fecal samples were collected from adult alpacas and crias (ages 10 wk to 10 yr) on two farms in central Maryland. The farms raised both suri (silky-haired) and huacaya (crimpy-haired) breeds. Females and crias were housed together on pasture, whereas older/breeding males were maintained on separate pastures. Samples were subjected to a density gradient centrifugation protocol to concentrate parasites and remove fecal debris and examined by immunofluorescent and differential interference contrast microscopy. Oocysts of Eimeria spp. were noted in 14 fecal samples, 6 on MD-1 and 8 on MD-2. Based on oocyst morphometrics two species of Eimeria were present: E. punoensis (19.2 x 16.5 µm) and E. alpacae (23.7 x 19.5 µm). Five animals shed exclusively E. punoensis, 7 shed exclusively E. alpacae, and 2 had mixed infections. The Eimeria infections were not associated with obvious clinical signs. To determine the presence of Cryptosporidium and Giardia species and genotypes, DNA was extracted from feces and subjected to PCR utilizing specific primers for the ssu-rRNA gene for both parasites. All PCR positive samples were further analyzed by DNA sequencing to identify the species or genotypes that were present. Assemblage A, G. duodenalis was detected in fecal samples from 2 alpacas on MD-1 and in 1 alpaca on MD-2. Assemblage E, G. duodenalis and Cryptosporidium spp. were not detected on either farm. Although the prevalence on these 2 farms was low, alpacas can harbor zoonotic G. duodenalis, and this should be borne in mind by persons interacting with the animals.