What is your diagnosis? Fecal smear stained with Lugol's solution and Giemsa from a cynomolgus macaque (Macaca fascicularis) presenting with liquid diarrhea

Blastocystis in domesticated and wild mammals and birds

Blastocystis is a ubiquitous parasite that infects a broad range of vertebrate hosts including humans and domestic and wild animals. While human infections have been occasionally associated with gastrointestinal illnesses and/or urticaria, animal infections are not usually associated with disease. However, from a public health perspective, most subtypes isolated in humans have also been isolated from animals raising the question of the importance of animal reservoirs in the epidemiology of this parasite. The identification of Blastocystis in water supplies suggests water can be a potential vehicle in the transmission of this parasite not only for humans but also for animals. In addition, Blastocystis has been detected in retail fresh produce. Knowledge of this parasite has greatly expanded in the last two decades from simple microscopic observations to the application of molecular tools to explore Blastocystis taxonomy and epidemiology. This review provides a comprehensive overview of Blastocystis in animals highlighting the subtype diversity of this widespread and genetically diverse parasite in different animal groups. This information will be useful in understanding the current status of taxonomy, epidemiology, zoonotic potential, and public health importance of Blastocystis.

Molecular epidemiology of Blastocystis sp. in dogs housed in Italian rescue shelters

Blastocystis is a ubiquitous protozoan with a wide range of hosts. In humans, its presence has been associated with gastrointestinal disorders, although its role as a pathogen still needs to be elucidated. Until now, 17 Blastocystis subtypes (STs) have been identified, with ST1-ST4 the most commonly found in humans. Among domestic animals, the same STs reported in humans have been detected in dogs. An epidemiological survey on dog kennels was carried out to evaluate the prevalence of Blastocystis and the STs involved. Overall, 99 faecal samples were collected from the rescue shelters. Blastocystis detection was performed through conventional barcoding PCR targeting the 1800-bp SSU-rDNA, followed by sequencing and phylogenetic analysis. Blastocystis DNA was found in 21 faecal samples (21.2%), and all samples were successfully sequenced and identified as ST3 in a unique monophyletic group. The presence of Blastocystis was reported for the first time in dogs from Italy, with the identification of ST3, the subtype most commonly found in humans.

Extra-enteric Blastocystis infection in a duck

Cell structures morphologically consistent with Blastocystis were aspirated from a subcutaneous facial swelling in a 13-mo-old pet duck. On PCR analysis and sequencing, the organism was confirmed as Blastocystis sp. subtype 7. Blastocystis is a single-celled protist that is found in the intestinal tract of many species, including mammals, birds, reptiles, amphibians, and insects. A complete understanding of the lifecycle and pathogenesis of the parasite remains elusive. Blastocystis has been implicated in human and animal disease; however, its role is controversial given that it is commonly found among healthy gut microbiota. Infection with Blastocystis outside the intestinal tract has been reported only rarely in humans. Our case of subcutaneous Blastocystis infection in a duck is a novel presentation of a ubiquitous, generally asymptomatic, parasite or commensal of the intestinal tract.

Study of the gastrointestinal parasitic fauna of captive non-human primates (Macaca fascicularis)

The aim of this study was to examine helminths and protozoans in cynomolgus macaques (Macaca fascicularis) imported from registered breeding facilities in China and their relation to health risks for non-human primate handlers in biomedical research centers and in breeding facilities. Fresh fecal samples were collected from a total of 443 M. fascicularis and analyzed by copromicroscopical analysis, immunoenzymatic, or molecular assays. As to helminths, whose eggs were shed in 2.03% of the samples, Trichuris and Oesophagostomum were the only two taxa found, with low prevalence and low eggs per gram (EPG) values. Protozoans were more frequently detected (87.40%), with Entamoeba coli (85.19%) and Endolimax nana (79.26%) as the most prevalent species shed. Other parasites found by fecal smear examination were uninucleated-cyst-producing Entamoebas (78.52%), Iodamoeba bütschlii (42.96%), and Chilomastix mesnili (24.44%), while cysts of Balantidium coli (22.2%) were only observed by sedimentation. No coproantigens of Giardia duodenalis, Cryptosporidium spp., and Entamoeba histolytica complex were detected. Blastocystis sp. infection was noticed in 87.63% of macaques by PCR. These cynomolgus monkeys were infected with many subtypes (ST1, ST2, ST3, ST5, and ST7), where the predominant Blastocystis sp. subtypes were ST2 (77.5%), followed by ST1 (63.5%). Data collected confirmed the presence of potentially zoonotic parasites and a high parasite diversity, suggesting the need for appropriate and sensitive techniques to adequately control them and related health risks for handlers of non-human primates in biomedical research centers and in breeding facilities.