Coccidioidomycosis in South America. A review of its epidemiology and geographic distribution

Abstract

Argentina. Twenty-seven human cases and coccidioidin skin-test surveys have located the endemic area of coccidioidomycosis between the 27th and 40th south parallels. Climate is of the arid steppe type in the southern zone, arid hill and prairie in the intermediate zone, and arid hill and prairie plus hot tropical in the northern zone. Temperature ranges from 5° C to 29° C, vegetation is xerophytic and annual rainfall is from 300 to 500 mm.

Paraguay. On the basis of human cases and coccidioidin surveys, the endemic area has been delimited between the 19th and 24th south parallels. It was a hot, dry, windy climate with temperature reaching 45° C, an annual rainfall average of 500 mm and xerophytic vegetation.

Colombia. On the basis of two human cases and coccidioidin test surveys, an endemic area of low prevalence was confirmed in the northeast between the 10th and 12th north parallels. Altitude in this region is from 2 to 300 meters above sea level, temperature averages about 29° C. Within this region two different areas can be differentiated — one in the north where vegetation is tropical desert brush type and rainfall ranges between 125 and 500 mm; the second in the south with grass and cotton culture and rainfall from 500 to 2000 mm.

Venezuela. Thirty-five human cases and nearly 60,000 skin tests made from east to west in the northern part of the country, where the population is concentrated, showed that the endemic area is situated between the 9th and 12th north parallels. This is an arid region with “desert soils”. Altitude ranges from sea level to 800 meters, annual temperature averages 24° C and rainfall 500 mm in some places, and 29° C and less than 400 mm in others. More than 172 species of plants have been identified in the zone but cacti predominate.C. immitis was isolated from soil collected at a site where a patient had become infected.

Bolivia, Peru and Ecuador.Mackinnon studied a patient coming from Bolivia, but he has expressed doubt about the Bolivian origin of the infection because the patient had lived in the Paraguayan Chaco the previous year. More information is necessary to evaluate the human case mentioned in Peru byBinder. Cases reported from Ecuador appear to have been paracoccidioidomycosis and leishmaniasis rather than coccidioidomycosis.

Many species of rodents and other wild and domestic animals share with man the possibility of infection in the four countries where the endemic areas have been confirmed.