A case-control study of calves under 3 months of age was carried out by weekly visits to 15 farms in the canton of Tilarán, Costa Rica. Most farms were dedicated to beef or dual-purpose (DP) production. Faecal samples were collected over a 6-month period from a total of 194 calves with clinical signs and from 186 animals without clinical signs of diarrhoea as assessed by a scoring system. The samples were investigated for the presence of viruses, bacteria and parasites. Torovirus was detected for the first time in Costa Rica and was present in 14% of calves with diarrhoea and in 6% of the controls. Coronavirus and Rotavirus were less frequently encountered in either one of the groups (in 9 and 7% of scouring calves and in 1 and 2% of controls, respectively). Escherichia coli was detected in 94% of all the faecal samples, but isolates from only three samples from calves with diarrhoea contained the K99 antigen. Similarly, Salmonella was found only in scouring calves. Cryptosporidium oocysts were detected in animals with signs of diarrhoea, while other coccidia oocysts, Strongylida and Strongyloides eggs were frequently found in animals both with and without diarrhoea. A conditional logistic regression (CLR) analysis to compare healthy and scouring calves showed a significant difference with regard to the presence of Torovirus, Rotavirus and Coronavirus.

Lower socioeconomic status (SES) has been associated with higher rates of HIV infection as well as higher rates of unsafe sex. The behavioral determinants that might mediate the effect of SES on risky sex have not been studied thus far. We investigated the involvement of social cognitions in the link between educational status and unprotected anal sex in 292 participants of the Amsterdam Young Gay Men Study. We found that poorly educated men had poorer knowledge about HIV and preventive behavior, perceived social norms to be less favorable towards condom usage with casual partners, and had lower perceived control over that behavior than the better educated men. Poorly educated men were also more likely to have engaged in unprotected anal sex with casual partners in the six-month period that followed the assessment of the social cognitions. However, the education-related behavioral difference could not be explained by social cognitions. We concluded that cognitive models of behavior might not explain all of the risk behavior in gay men with lower SES. These men's risk-taking behavior might result from specific psychological characteristics of men with lower SES that interfere with traditional cognition-behavior correlations as posited in prevailing models of behavior.

We have characterized two group O viruses, originating from Cameroon and Gabon, which show a close evolutionary relationship to ANT70 and four Ha strains based on the entire env gene, suggestive of a first group O subgroup, tentatively named the HIV-1 group O env ANT70 clade or subtype.

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Guinea pigs were inoculated intra‐tracheally with bovine parainfluenza type 3 virus (PI‐3) to investigate whether airway hyperreactivity was associated with an increase in the number of broncho‐alveolar cells. Two days after saline or PI‐3 inoculation no difference in histamine reactivity of the isolated tracheal spirals was observed. The number of broncho‐alveolar cells was also not changed. However, 4 days after PI‐3 inoculation the histamine‐induced contraction of the tracheal spirals was increased by 45% and the number of inflammatory cells in the airways by 150% as compared with the control group. In conclusion, PI‐3 infection of the guinea pig respiratory airways induces tracheal hyperreactivity which is associated with an increase in broncho‐ alveolar cells.

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