Transmission and control implications of seroconversion to Maedi-Visna virus in Basque dairy-sheep flocks.

A retrospective analysis of seroconversion to Maedi-Visna virus (MVV) was carried out for 10 infected semi-intensively reared dairy-sheep flocks that were tested annually between 1994 and 1999. Four of the flocks raised replacement lambs artificially with bovine colostrum and milk replacement to avoid lactogenic MVV infection but did not prevent aerosol contact between replacements and other sheep in the flock. Flock culling percentages ranged between 14 and 25% and in eight flocks the number of sheep that seroconverted was similar to or lower than the number of sheep culled--suggesting that incidence could be reduced by culling seropositive sheep without increasing average culling percentages.

The Quechua manta pouch: a caretaking practice for buffering the Peruvian infant against the multiple stressors of high altitude.

The manta pouch--a caretaking practice of tightly swaddling and enclosing the infant in a set of cloths and blankets--and other caretaking practices are described for high-altitude resident (> 4,000 m) Quechua mother-infant pairs (N = 14). The manta pouch modifies the microenvironment inside the pouch so that, compared to the ambient environment, the temperature is higher and more stable, the humidity is higher, the partial pressure of O2 is lower, and stimulation levels are reduced. As the infant gets older, the characteristics of the pouch are modified such that the infant is increasingly exposed to ambient conditions.

Recessive inheritance of the adult type of intestinal lactase deficiency.

In order to investigate the genetic control of the adult type of intestinal lactase deficiency, 61 families with 177 children over 6 years of age were investigated. The results strongly suggest that this deficiency is inherited as a simple Mendelian recessive trait.