Mosquitoes of British Honduras, with some comments on malaria, and on arbovirus antibodies in man and equines.

This study records a 1967 survey of mosquitoes in British Honduras, revealing a collection of 65 species and examining the presence of malaria and arbovirus, including common vectors for these diseases. The study shows an increase in mosquito densities during the rainy season, explores diurnal activities, nocturnal habits, and distribution, and reports an absence of the Aedes aegypti mosquito following an eradication program.

Survey and Species Identification

• The mosquito survey conducted in 1967 in British Honduras, encompassing coastal, river, and forest conditions, resulted in the identification of 65 distinct mosquito species. These were divided into several classifications such as Anopheles, Aedes, and Haemagogus among others.
• The study surfaces a new species, Aedes bertrami, as part of the Aedes terrens group. It was identified in similar ecological zones as other related species like Aedes cozumelensis, which was found for the first time in the Yucatan in Mexico, 1966, and Mansonia dyari, initially identified in Jamaica, 1970.
• The study did not find the Aedes aegypti mosquito, due to previous intensive efforts to eradicate the species which is known to carry the dengue, zika, chikungunya, and yellow fever viruses.

Mosquito Density and Seasonality

• While relatively low during the dry season (April-May), mosquito densities greatly increased with the onset of the rainy season from late May or June, forming the peak population period until the dry season of the following year.
• With a similar pattern to other regions in Middle America, mosquitoes showed diurnal (daytime), crepuscular (twilight), and nocturnal (nighttime) activity, and dependency on forest zones for their population spread and propagation.

Malaria and Arbovirus Observations

• The species identified function as vectors for diseases such as malaria and different arboviruses. In relation to malaria, despite the presence of mosquito vectors, the incidence of the disease was low, attributed to comprehensive malaria control efforts pre-dating the study.
• In 1967, Venezuelan equine encephalitis (VEE) antibodies were found in equines and the VEE virus was isolated from sentinel hamsters in the vicinity of Belize City. However, the human population has largely avoided major infections in recent years, evident from antibody tests of humans for VEE, St. Louis encephalitis (SLE), and Ilheus viruses.
• No definitive evidence of arbovirus infections was found amongst the British garrison troops, possibly due to their location or company-wide health measures.
• The research noted that equines within British Honduras avoided a major widespread VEE outbreak until October 1971. This was despite the disease affecting multiple Central American countries since 1969. The region was spared largely due to proactive vaccination programs, especially for horses in zones bordering Mexico and Guatemala, which were severely affected by the outbreak.