Close kinship within multiple-genotype malaria parasite infections.

Malaria infections containing multiple parasite genotypes are ubiquitous in nature, and play a central role in models of recombination, intra-host dynamics, virulence, sex ratio, immunity and drug resistance evolution in Plasmodium. While these multiple infections (MIs) are often assumed to result from superinfection (bites from multiple infected mosquitoes), we know remarkably little about their composition or generation. We isolated 336 parasite clones from eight patients from Malawi (high transmission) and six from Thailand (low transmission) by dilution cloning. These were genotyped using 384 single-nucleotide polymorphisms, revealing 22 independent haplotypes in Malawi (2-6 per MI) and 15 in Thailand (2-5 per MI). Surprisingly, all six patients from Thailand and six of eight from Malawi contained related haplotypes, and haplotypes were more similar within- than between-infections. These results argue against a simple superinfection model. Instead, the observed kinship patterns may be explained by inoculation of multiple related haploid sporozoites from single mosquito bites, by immune suppression of parasite subpopulations within infections, and serial transmission of related parasites between people. That relatedness is maintained in endemic areas in the face of repeated bites from infected mosquitoes has profound implications for understanding malaria transmission, immunity and intra-host dynamics of co-infecting parasite genotypes.

Chronic disease and disasters medication demands of Hurricane Katrina evacuees.

BACKGROUND: Preparing for natural disasters has historically focused on treatment for acute injuries, environmental exposures, and infectious diseases. Many disaster survivors also have existing chronic illness, which may be worsened by post-disaster conditions. The relationship between actual medication demands and medical relief pharmaceutical supplies was assessed in a population of 18,000 evacuees relocated to San Antonio TX after Hurricane Katrina struck the Gulf Coast in August 2005. METHODS: Healthcare encounters from day 4 to day 31 after landfall were monitored using a syndromic surveillance system based on patient chief complaint. Medication-dispensing records were collected from federal disaster relief teams and local retail pharmacies serving evacuees. Medications dispensed to evacuees during this period were quantified into defined daily doses and classified as acute or chronic, based on their primary indications. RESULTS: Of 4,229 categorized healthcare encounters, 634 (15%) were for care of chronic medical conditions. Sixty-eight percent of all medications dispensed to evacuees were for treatment of chronic diseases. Cardiovascular medications (39%) were most commonly dispensed to evacuees. Thirty-eight percent of medication doses dispensed by federal relief teams were for chronic care, compared to 73% of doses dispensed by retail pharmacies. Federal disaster relief teams supplied 9% of all chronic care medicines dispensed. CONCLUSIONS: A substantial demand for drugs used to treat chronic medical conditions was identified among San Antonio evacuees, as was a reliance on retail pharmacy supplies to meet this demand. Medical relief pharmacy supplies did not consistently reflect the actual demands of evacuees.