Removing the men who have sex with men blood donation deferral: Informing risk models using Canadian public health surveillance data.

OBJECTIVE: Gay, bisexual and other men who have sex with men (gbMSM) were ineligible to donate blood in most countries since the 1980's. In Canada the deferral period has been incrementally decreased from lifetime to male-to-male sex in the last 3 months. Now a few countries have removed the deferral altogether. Risk models have been utilised to estimate the probability of an HIV positive donation being released into the blood supply and to inform incremental changes to the length of the deferral period. Here we use public health data to estimate the risk of HIV if the gbMSM deferral criteria were removed in Canada. MATERIAL AND METHODS: We calculate the risk reduction among heterosexuals based on responses to standard risk questions routinely asked of donors. We assume gbMSM will donate at the same rate as heterosexual males. We apply the same risk reduction principle to HIV incidence and prevalence among gbMSM in the general population to evaluate the HIV risk without gbMSM time deferral. We model three scenarios where risk reduction is varied by assumptions about incidence and compliance with deferral criteria. RESULTS: The estimates for all scenarios were not significantly different to the currently observed scenario which predicts a residual risk of 0.02 HIV positive per million donations (95% CI: 0.000006-0.09). CONCLUSION: The models predict that removing the gbMSM deferral criteria would result in HIV residual risk similar to currently observed.

Factors affecting mortality risk during transportation of broiler chickens for slaughter in Atlantic Canada.

Mortality of broilers during transport and lairage before slaughter represents an economic loss to the poultry industry and a welfare issue that needs to be addressed. In Canada, broilers can be transported long distances and be exposed to environmental factors, such as cold temperatures, that can affect the percentage of dead-on-arrivals or DOAs. Slaughter plant records for loads transported over a 19-month period in 2009-2010 were examined to identify factors affecting mortality risk (% DOA) during transportation from the rearing barn to the slaughter plant. Information from 2007 loads was analysed using a multilevel linear model. Most of the variation in the mortality risk occurred at the load level rather than at the producer or barn level. There were significant effects of bird sex, age and weight, catching team, journey duration and holding barn duration on mortality risk. The following environmental risk factors increased mortality risk: cold temperatures during the journey and in the holding barn, low crate stocking density during journeys at cold temperature and increased trailer temperature when in the holding barn. The analyses identified risk factors that can be used to refine management practices to mitigate some of the mortality risk. Increased mortality in some loads was associated with environmental conditions that caused deaths from hypothermia, whereas in other circumstances, some deaths likely occurred from hyperthermia. The climatic conditions in Atlantic Canada were responsible for significant risk factors that affected the mortality risk. Although refinement of the management practices described in this study, such as reduced journey and lairage durations, and increased crate stocking density can mitigate some of the mortality risk, the extreme cold conditions experienced during some parts of the year exceeded the capacity of the systems of transportation used to provide environmental conditions that minimise mortality.