Replacement of Aedes aegypti by Aedes albopictus in Mobile, Alabama.

Aedes albopictus was first detected in Mobile, AL, in 1987 during a CDC sponsored ovitrap survey in the Historic District. A comparison of ovitrap and larval surveys, done in 1957, 1984, 1987 and 1990, indicates that Ae. albopictus had replaced Aedes aegypti in urban Mobile. Possible explanations of this replacement, including displacement, are discussed.

Microplate assay analysis of reduced fenitrothion susceptibility in Haitian Anopheles albimanus.

Reduced fenitrothion susceptibility in Haitian Anopheles albimanus is documented using time/mortality measurements from otherwise standard World Health Organization (WHO) bioassays. Survival beyond a time threshold in bioassays is shown to be highly correlated with elevated non-specific esterase levels. A shift in resistance incidence from less than 20 to over 60% in a six-month period is documented using both the bioassay and microassay procedures, showing the potential of microplate assay methods in early detection of resistance. Conventional 24-hour reading of WHO bioassay data failed to detect resistance until the level reached 60%. Resistance appeared to be focal, with an increase in intensity coinciding with a fenitrothion spray cycle for malaria control.

The biting and resting behavior of Anopheles albimanus in northern Haiti.

A one-year study of the biting and resting habits of the malaria vector Anopheles albimanus was carried out in four rural villages of northern Haiti. Man-biting rates and nightly biting cycles were determined by the use of all-night man-biting captures inside and outside houses. Seasonal changes in density and behavior were determined by repeating the captures on a bimonthly basis throughout one year. Exophily was demonstrated in these anopheline populations by a comparison of inside-biting with inside-resting densities. These behavior characteristics are discussed in relation to malaria transmission and to the choice of malaria control methods.

Comparison of an experimental updraft ultraviolet light trap with the CDC miniature light trap and biting collections in sampling for Anopheles albimanus in Haiti.

Three methods of capturing Anopheles albimanus mosquitoes were compared during a field study in four villages in northern Haiti. Updraft ultraviolet (UV) light traps proved to be more effective than biting collections, regardless of season or whether the tests were done indoors or outdoors. Biting collections were in turn more effective than the Centers for Disease Control (CDC) miniature light traps. Updraft UV light traps and biting collections yielded more An. albimanus outdoors than indoors; the reverse was found for the CDC miniature light traps. The updraft UV light traps caught An. albimanus on 86% of the occasions used outside and 75% of the occasions inside. The biting collections were equally as successful as the traps in catching mosquitoes outside but caught An. albimanus only on 64% of the occasions when used inside houses. The CDC miniature light traps were successful in collecting An. albimanus on 33% of the occasions outside and 60% of the occasions inside.

Assessment of chloroquine sensitivity of Plasmodium falciparum in Choluteca, Honduras.

During an outbreak of urban malaria in Choluteca, Honduras, the response of local isolates of Plasmodium falciparum to chloroquine was assessed. The 7-day WHO alternative standard field test was used together with three in vitro tests: the Rieckmann macro- and micromethods and a new 48-hour test which underwent its first field trial in this study. No chloroquine resistance was found in in vivo tests in 10 patients or in the in vitro tests on blood samples from 6 patients.

Safety measures associated with the use of organophosphate insecticides in the Haitian malaria control programme.

A programme emphasizing intensive training, use of protective equipment and uniforms, daily supervision of safety measures at work, and weekly monitoring of blood cholinesterase levels by the tintometric method was instituted to prevent toxicity in Haitian malaria workers during spraying with the organophosphate insecticides fenitrothion and malathion. The programme functioned well, depressed cholinesterase activity (

Tularemia pneumonia in Washington, DC. A report of three cases with possible common-source exposures.

In June 1978, three cases of tularemia pneumonia occurred in persons residing in the Washington, DC, area. The patients, all men, became ill three to four days after a brief session training their hunting dogs in an undeveloped wooded area adjacent to a housing complex. One of the dogs, which later died, had captured a wild rabbit during the training session. All three men had handled the rabbit while familiarizing their dogs with the rabbit's scent. The men had no other common exposure that was a likely source of infection.

An apparent outbreak of rickettsial illness in Costa Rica, 1974.

A focal outbreak of highly fatal disease occurred in eastern Costa Rica in 1974. No rickettsial spotted fevers have previously been reported in Costa Rica. Nevertheless, the available evidence points to an unidentified rickettsial pathogen, probably of the spotted fever group, as the agent responsible for this outbreak.