Ground zero: AIDS research in Africa

More and more European and North American AIDS researchers are coming to sub-Saharan Africa, which is home to a whopping 70% of all HIV-infected people. These investigators are collaborating with local researchers on projects that aim to slow both HIV's spread and the course of disease in the millions already infected. But most African countries--constrained by limited resources, weak infrastructures, social mores, and political inaction--have grave difficulties translating research insights into prevention and treatment strategies.     

Is AIDS in Africa a distinct disease?

In Africa, opportunistic infections, transmission patterns, and viral subtypes differ from what is seen in the AIDS epidemics of the United States and Europe, yet 2 decades into the epidemic, AIDS researchers have only a shaky handle on the fundamental question: What accounts for these differences? The answers have potentially important implications for both prevention and treatment strategies.     

Balancing the collaboration equation

Most African countries can't afford to support much research themselves, so the vast majority of studies of HIV/AIDS are being conducted in collaboration with scientists from the developed world. These partnerships have brought major benefits, but inherent inequalities can cause tensions and require constant give-and-take from both sides. An inside look at three veteran marriages between African AIDS researchers and foreign colleagues illustrates the benefits--and stresses--of partnership.     

Profile. Preventing infections with today's tools

With no vaccine in sight powerful enough to halt the spread of HIV, Africa is left with one strategy to combat the epidemic: prevention. The University of Manitoba's Frank Plummer, who oversees a large research collaboration in Nairobi, Kenya, says his group has identified a half-dozen effective interventions to lower HIV transmission rates, but "the scale at which they're implemented is tiny."     

Profile: McIntyre and Gray have a will and a way

At the Chris Hani Baragwanath Hospital here, where HIV infects more than 20% of the 17,000 pregnant women who give birth here each year, pediatrician Glenda Gray and obstetrician James McIntyre aggressively try to help HIV-infected pregnant women stop the virus from infecting their babies.     

Profile: a native son comes home to help

In December 1996, Omu Anzala returned to Kenya after completing his Ph.D. work in Canada on HIV's interactions with the immune system to work with a collaborative AIDS research project started by researchers from his university and the University of Manitoba. Now the International AIDS Vaccine Initiative has funded Anzala and his collaborators to fashion an AIDS vaccine based on a strain of HIV circulating in Kenya.     

Dissociating the role of the dorsolateral prefrontal and anterior cingulate cortex in cognitive control

Theories of the regulation of cognition suggest a system with two necessary components: one to implement control and another to monitor performance and signal when adjustments in control are needed. Event-related functional magnetic resonance imaging and a task-switching version of the Stroop task were used to examine whether these components of cognitive control have distinct neural bases in the human brain. A double dissociation was found. During task preparation, the left dorsolateral prefrontal cortex (Brodmann's area 9) was more active for color naming than for word reading, consistent with a role in the implementation of control. In contrast, the anterior cingulate cortex (Brodmann's areas 24 and 32) was more active when responding to incongruent stimuli, consistent with a role in performance monitoring.     

A discrete-event computer model of feline herpes virus within cat populations

The purpose of this work was to study the epidemiology of feline herpes virus (FHV), which causes a respiratory disease within natural populations of domestic cats. A stochastic model was constructed using discrete-events simulation. Two habitats (rural vs. urban) were simulated, featuring different demographic, spatial and social patterns. The evolution of immunity in individuals was reproduced, allowing for the random recrudescence of latent infections (influenced by environment and reproduction). Hypotheses concerning the circulation of FHV were examined regarding the role of host density and the possibility of reinfection of host. Uncertainty analyses were performed on the basis of replicated Monte Carlo sampling. The results were in good agreement with serologic data from a long-term study conducted on five populations in France. The model satisfactorily reproduced the variability of natural immunity, and the epidemic features observed. The simulations have shown that FHV can persist in small populations (because of its capacity of reactivation leading to epidemics). However, the impact on demography was not dramatic. The most important parameters in determining change in epidemiology of FHV were: transmission rate corresponding to ‘friendly’ contacts, and the recrudescence rate of FHV. However, an interaction between these two parameters did not allow estimation of their values.