Page 104 - parasitology for medical and clinical laboratoryprofessionals

84 CHAPTER 4

TABLE 4-3 Leishmania braziliensis Complex—Mucocutaneous Seishmaniasis

GEOGRAPHI- RESERVOIR
ORGANISM FORM OF DISEASE VECTOR CAL REGION HOSTS
L. braziliensis Mucocutaneous form Lutzomyia and Rainforests Animals
around mouth and nose Psychodopygus sand flies (zoonoses)
L. panamensis Mucocutaneous form Lutzomyia and Panama, Animals
around mouth and nose Psychodopygus sand flies Colombia (zoonoses)
L. peruviana Mucocutaneous form Lutzomyia and Peruvian Andes Animals
around mouth and nose Psychodopygus sand flies (zoonoses)
L. guyamensis Mucocutaneous form Lutzomyia and Guianas, parts Animals
around mouth and nose Psychodopygus sand flies of Brazil and (zoonoses)
Venezuela

TABLE 4-4 Leishmania donovani Complex—Visceral Leishmaniasis

Viserotropic—Infects reticuloendothelial cells; infected macrophages are disseminated throughout the body.
GEOGRAPHICAL
ORGANISM FORM OF DISEASE VECTOR REGION *RESERVOIR HOSTS
L. donovani Diffuse cutaneous form Lutzomyia India, Pakistan, Rodents and dogs
sand fly Thailand, parts of
Africa, Peoples
Republic of China
L. infantum Diffuse cutaneous form Lutzomyia Europe, Africa, the Domestic dogs, other canids,
sand fly Near East, parts of porcupines
former Soviet Union
L. chagasi Both cutaneous and Lutzomyia Central and South Foxes, domestic dogs and cats
diffuse cutaneous forms sand fly America

* In India, humans are the only mammalian reservoir.

the red blood cells are sometimes inadvertently found in fifth century BC. The disease was variously believed to
in the blood of asymptomatic patients during routine be an example of demons afflicting humans, as references
blood tests (Figure 4-5). Similar parasites are common in to the disease are found in literature from Greece and
monkeys and apes. It is now generally held that malaria Italy, and in the areas governed by the Roman Empire.
arose in our primate ancestors in Africa and evolved with Certain climactic conditions and the availability of
humans, spreading with human migrations first through- suitable vectors that contribute to the transmission of ma-
out the tropics, subtropics, and temperate regions of the laria must be present in order for the disease to be trans-
Old World and then to the New World with explorers, mitted and to survive and continue to infect individuals.
missionaries, and slaves. The characteristic periodic fe- Eventually it became somewhat obvious to scientific
vers of malaria are recorded from every civilized society investigators that malaria was somewhat endemic in
from China in 2700 BC through the writings of Greek, marshy areas, and was not as frequently observed in dry
Roman, Assyrian, Indian, Arabic, and European physi- areas with no standing bodies of water. Originally the
cians up to the nineteenth century. The earliest detailed disease was attributed to the vapors from the marshes,
accounts are perhaps from observations by Hippocrates but perhaps there became a gradual realization that in