Ancestry analysis of locally adapted Crespa goats from southernmost Brazil.

Crespa goats are phenotypically similar to the Angora breed, and are traditionally reared in small, low-tech farms in southernmost Brazil. Whether they represent degenerated remnants of pure Angora goats or result from foreign breeds introduced during colonial times and recently mixed with commercial breeds is unknown. Since the degree of relatedness of Crespa in relation to other goats is completely unknown, we performed a comparative assessment of the genetic similarity between Crespa and foreign commercial breeds reared in the region (Angora, Alpine, Anglo-Nubian, Boer, and Saanen), particularly the Angora. We used 11 microsatellites to score alleles in 148 individuals and performed a Bayesian assignment test, which revealed six clusters (K = 6; Ln likelihood = -5047.6). In addition, a segment of the mitochondrial DNA (mtDNA) control region was sequenced to investigate the relatedness of Crespa goats to Portuguese autochthonous breeds (Algarvia, Bravia, Charnequeira, Serpentina, and Serrana). The origin of the Crespa breed could not be ascertained from the mtDNA, but it does not only descend from the Angora. It is probably related to other introduced and autochthonous Portuguese breeds, in particular the Algarvia. Therefore, our results indicate that this distinctive source of genetic diversity is partly a remnant of animals that were introduced during the colonial period. By recognizing it as genetically distinct, we provide further support for the protection of this particular gene pool.

Seven years' experience with Cryptosporidium parvum in Guinea-Bissau, West Africa.

In community-based studies conducted from 1991 to 1997 in Guinea-Bissau, West Africa, stool specimens from children aged less than 5 years with diarrhoea were routinely examined for enteric parasites. Cryptosporidium parvum, found in 7.7% of 4,922 samples, was the second most common parasite, exceeded only by Giardia lamblia which was found in 14.8% of the samples. The highest prevalence of cryptosporidium was found in children aged 6-11 months, whereas the prevalence of other enteric parasites increased with age. Cryptosporidiosis showed a marked seasonal variation, with peak prevalences found consistently at the beginning of or just before the rainy seasons, May through July. By contrast, no seasonality was found for the enteric parasites Giardia lamblia or Entamoeba histolytica. We conclude that Cryptosporidium parvum is an important pathogen in children with diarrhoea.