Epidemiology of Cryptosporidium: transmission, detection and identification.

Biology, persistence and detection of Cryptosporidium parvum and Cryptosporidium hominis oocyst.

Using DNA sequencing and phylogenetic analysis, we identified four distinct Cryptosporidium genotypes in HIV-infected patients: genotype 1 (human), genotype 2 (bovine) Cryptosporidium parvum, a genotype identical to C. felis, and one identical to a Cryptosporidium sp. isolate from a dog. This is the first identification of human infection with the latter two genotypes.

New cryptosporidium genotypes in HIV-infected persons.

Herpesvirus saimiri (H. saimiri) is a ubiquitous agent of squirrel monkeys (Saimiri sciureus), a primate species native to the South American rain forests. The virus can easily be isolated from blood and tissue-culture cells of most healthy squirrel monkeys, and there is no evidence so far that H. saimiri is pathogenic in its natural host. After the first report on isolation of H. saimiri from primary kidney-cell cultures by Melendez et al. (1968) from the New England Primate Research Center, the virus was regarded as a harmless indigenous agent of squirrel monkeys. The interest in this virus arose from the observation that H. saimiri is extremely oncogenic in a number of other primate species that are presumably not infected under usual wildlife conditions (Melendez et al., 1969b). Marmoset monkeys of the genus Saguinus consistently develop malignant tumors of the lymphatic system, usually within 2 months of infection. The ability to induce neoplastic disease rapidly and reproducibly has made this system attractive for investigation of the biological, immunological, and molecular parameters of Cell transformation and tumor induction.

Herpesvirus saimiri and Herpesvirus ateles

Cryptosporidium is an important cause of enteric disease in humans and other animals. Limitations associated with conventional diagnostic methods for cryptosporidiosis based on morphological features, coupled with the difficulty of characterising parasites isolated in the laboratory, have restricted our ability to clearly identify species. The application of sensitive molecular approaches has obviated the necessity for laboratory amplification. Such studies have found considerable evidence of genetic heterogeneity among isolates of Cryptosporidium from different species of vertebrate, and there is now mounting evidence suggesting that a series of host-adapted genotypes/strains/species of the parasite exist. In this article, studies on the molecular characterisation of Cryptosporidium during the last 5years are reviewed and put into perspective with the past and present taxonomy of the genus. The predictive value of achieving a sound taxonomy for the genus Cryptosporidium with respect to understanding its epidemiology and transmission and controlling outbreaks of the disease is also discussed.

Variation in Cryptosporidium: towards a taxonomic revision of the genus (Review)

Cryptosporidium parvum is a protozoan parasite that causes the disease cryptosporidiosis in a variety of mammals, including neonatal calves and humans. Millions of oocysts are shed during acute cryptosporidiosis, and zoonotic transmission is inferred, though not proven, to be a general phenomenon. Very little is known about the degree of strain variation exhibited by bovine and human isolates, though such knowledge would enable the amount of bovine-to-human transmission to be more precisely analyzed. This research was initiated to determine whether variations exist among bovine strains isolated from a localized geographic area, the watershed of the Red River of the North. Sixteen strains were isolated and compared to each other and to two human and two calf strains from Australia by randomly amplified polymorphic DNA PCR. A statistical analysis of the data indicated that the isolates belonged to four different groups of strains.

Russell Rytter

Papers

Randomly amplified polymorphic DNA PCR analysis of bovine Cryptosporidium parvum strains isolated from the watershed of the Red River of the North.

Herpesvirus saimiri: Viability in Four Species of Hematophagous Insects and Attempted Insect Transmission to Marmosets