Gastrointestinal cryptosporidiosis in a puppy

A canine model of experimental infection with Cryptosporidium canis

Cryptosporidium is a genus of protozoal parasites that affects the gastrointestinal epithelium of a variety of hosts. Several models of experimental infection have been described to study the susceptibility, infectivity and pathogenicity among different Cryptosporidium species and isolates. This study aimed to establish an experimental infection of Cryptodporidium canis in canids. Infectivity and pathogenicity have been measured by evaluating the clinical status, pattern of oocyst excretion and histological examination. Results showed that C. canis was not infective for immunocompetent dogs or mice with severe combined immunodeficiency syndrome (SCID). Oocysts were first detected in the feces of immunosuppressed dogs on day 3 post-infection (p.i.), with levels peaking twice on days 10 and 17 p.i. during the patent period. cryptosporidial developmental stages were found in the duodenum and jejunum of dogs in histological sections stained with hematoxylin and eosin (H & E) and using scanning electron microscopy (SEM). Histopathological changes in the intestinal tract of infected dogs were characterized by epithelial metaplasia and dilatation; the integrity of intestinal mucosal epithelial cells was distinctly damaged with whole sheets of cilia sloughed away. Ultrastructural observation data were consistent with histological observations. Based on these findings, the canine model described in this work will be useful to evaluate clinical, parasitological and histological aspects of C. canis infection and will be useful for the further understanding of cryptosporidiosis, drug development, and vaccine development.

AVALIAÇÃO DE FATORES EPIDEMIOLÓGICOS E SANITÁRIOS ASSOCIADOS À INFECÇÃO POR Cryptosporidium spp. EM CÃES DOMICILIADOS

Resumo O gênero Cryptosporidium é composto por protozoários com grande capacidade de reprodução e disseminação. Sua transmissão pode ocorrer indiretamente pela ingestão de água e alimentos contaminados com oocistos viáveis ou diretamente entre animais, entre humanos ou entre animais e humanos. Em diversas partes do mundo, animais de companhia tem sido citados como fontes potenciais de infecção por Cryptosporidium spp. O presente estudo teve como objetivo avaliar a ocorrência da infecção por Cryptosporidium spp. em cães domiciliados na cidade do Recife, estado de Pernambuco, Brasil, bem como a associação da infecção com dados epidemiológicos e sanitários. Foram analisadas 97 amostras de fezes de caninos domiciliados, utilizando-se as técnicas de centrífugo-sedimentação em formol-éter com posterior coloração pelo método de Kinyoun. A análise estatística foi realizada por meio dos testes Qui-quadrado de Pearson e Exato de Fisher, com nível de significância de 5,0%. Detectou-se positividade de 31,9% (31/97), tratando-se do primeiro registro de ocorrência da infecção por Cryptosporidium spp. na espécie canina no nordeste brasileiro, verificando-se associação significativa entre a taxa de infecção e a assistência médica veterinária, vacinação recebida e o tipo de ambiente de criação dos cães.

Occurrence and molecular characterization of Cryptosporidium in dogs in Henan Province, China

Background

Cryptosporidiosis in dogs has been reported worldwide, involving both asymptomatic and diarrheic dogs. Large-scale surveys of Cryptosporidium infection in dogs have been performed in some countries using differents diagnostic methods. But, few data are available on the infection rate and molecular characteristics of Cryptosporidium spp. in dogs in China.

Result

In this study, 770 fecal samples from 66 locations in Henan Province were examined. The average Cryptosporidium infection rate was 3.8%, with dogs in kennels having the highest rate of 7.0% (χ² = 14.82, P < 0.01). The infection rate was 8.0% in dogs younger than 90 days, which was significantly higher than that in the other age groups (1.1–3.8%;χ² = 18.82, P < 0.01). No association was noted between the infection rate and the sex of the dogs. Twenty-nine Cryptosporidium-positive samples were amplified at the small subunit rRNA (SSU rRNA), 70-kDa heat shock protein (HSP70), and actin loci using PCR. Sequence analysis of these amplicons identified only Cryptosporidium canis, which showed 100% identity with the published sequences of the SSU rRNA, HSP70, and actin genes.

Conclusions

Our results confirm that C. canis is popular in the dog population in China, considering the large number of dogs in China and the close contact between dogs and humans, the role of C. canis in the transmission of human cryptosporidiosis warrants attention.

DIAGNOSTIC EXERCISE

An approximately one-and-a-half-year-old, neutered male, mixed-breed dog was presented for a chronic history of vomiting. Profuse diarrhea was also noted during examination. An exploratory laparotomy was performed, bone chips were removed from the stomach, and a raised, circular area of gastric mucosa was biopsied. Histologically, there was severe gastric cryptosporidiosis as well as numerous spiral bacteria, consistent with Helicobacter spp. Polymerase chain reaction revealed visible bands for the 18S ribosomal RNA gene for Cryptosporidium spp. The polymerase chain reaction product was sequenced and was found to be most similar to Cryptosporidium muris. Both the gastric location and the species of Cryptosporidium are unusual in a dog.