Leonidas M. Deane

Anopheline species, some of their habits and relation to malaria in endemic areas of Rondônia State, Amazon region of Brazil

In view of recent studies incriminating several species of anophelines, besides Anopheles darlingi, as malaria vectors in the Brazilian Amazon, we performed an anopheline survey in four localities--Ariquemes, Cujubim, Machadinho and Itapoã do Oeste--in Rondônia, the most malarious State in the Country. Twenty species were found. An. darlingi was, by far, the dominant species and the only one whose density coincided with that of malaria. On human baits it was more numerous in the immediate vicinity of houses than indoors where, however, it was almost the only species encountered. On both situations it fed mostly at sunset and during the first half of the night. It was less numerous far from houses and scarce inside the forest. Other species (An. triannulatus, An. evansae, An. albitarsis, An. strodei) appeared in appreciable numbers only in Ariquemes, both in areas with and without malaria. The remaining species were scanty. An. darlingi was confirmed as the primary local vector.

Simian malaria in Brazil

In Brazil simian malaria is widely spread, being frequent in the Amazon region (10% of primates infected) and even more in the forested coastal mountains of the Southeastern and Southern regions (35% and 18% infected, respectively), but absent in the semi-arid Northeast. Only two species of plasmodia have been found: the quartan-like Plasmodium brasilianum and the tertian-like P. simium, but the possible presence of other species is not excluded. P. brasilianum is found in all enzootic foci, but P. simium was detected only on the coast of the Southeastern and Southern regions, between paralles 20 degrees S and 30 degrees S. Nearly all hosts are monkeys (family Cebidae, 28 species harbouring plasmodia out of 46 examined), and very rarely marmosets or tamarins (family Callitrichidae, 1 especies out of 16). P. brasilianum was present in all infected species, P. simium in only two. The natural vector in the Southeastern and Southern regions was found to be Anopheles cruzi, but has not been conclusively identified in the Amazon. One natural, accidental human infection due to P. simium was observed. There is no evidence of the relation of simian to human malaria in the Southeastern and Southern regions, where human malaria was eradicated in spite of the high rates of monkeys infected, but in the Amazon recent serological studies by other workers, revealing high positivity for P. brasilianum/P. malariae antibodies in local indians, would suggest that among them malaria might possibly be regarded as a zoonosis.

A morphological, isoenzymatic and behavioural study of ten populations of Anopheles(Nyssorhynchus) albitarsis Lynch-Arribalzaga, 1878 (Diptera: culicidae) including from the type-locality - Baradero, Argentina

Anopheles (Nyssorhynchus) albitarsis Lynch-Arribalzaga, 1878 shows morphological and behavioural variations which results in it being sometimes considered as a major malaria vector and at other times as playing no important role in epidemiology. With the aim of clarifying the taxonomy of the species, comparative morphological and isoenzymatic studies were made in populations from the type-locality, Baradero, Argentina and from 9 different localities inBrazil. Morphological studies consisted of the observation of eggs in scanning electron microscopy, of complete chaetotaxy of larvae and pupae and of the detailed drawing of male and female adults. Only Guajara-Mirim and Rio Branco populations, described previously as Anopheles deaneorum sp.n., showed morphological differences. Isoenzymes were studied using 4th instar larvae homogenate and agarosegel electrophoresis. Eleven enzymatic loci were analyzed. By calculation of Neis Genetic Distance (D), the populations could be separated into 5 groups: i)Baradero, ii)Marajo, iii)Boa Vista, iv)Angra, Itaguai and Paraipaba and v)Guajara-Mirim and Rio Branco. These groups belong to 2 major clusters called I and II, separated by D = 0.345. In the I cluster are groups i, ii and iii and in II clusteriv and v. In I, D=0.246 separates i and ii from iii, while i is separated by D =0.181 from ii. In II, D = 0.223 between iv and v. Only the population of group vcould be distinguished morphologically from the others, leading to the description of an independent species An. deaneorum.

The vertical dispersión of Anopheles (Kerteszia) cruzi in a forest in southern Brazil suggests that human cases of malaria of simian origin might be expected

By staining females of Anopheles cruzi with fluorescent coloured powders in a forest in the State of Santa Catarina, we showed that they move from canopy to ground and vice-versa to feed. This suggests that in areas where this mosquito is a vector of human and simian malarias sporadic infections of man with monkey plasmodia might be expected.

Simian malaria at two sites in the Brazilian Amazon. I--The infection rates of Plasmodium brasilianum in non-human primates

The parasite that causes simian malaria in the Brazilian Amazon, Plasmodium brasilianum, is infective to man. In this region, where humans live within and in close proximity to the forest, it was suspected that this parasite could be the cause of a zoonosis. A study was performed in the areas surrounding two hydroelectric plants in the Amazon, Balbina and Samuel, aiming at determining the zoonotic potential of this parasite. P. brasilianum was detected in, respectively, 15.8% and 9.9% of 126 and 252 primates belonging to seven and eight species examined from Balbina and Samuel. The highest malaria infection rates were found among the red-howler monkey Alouatta seniculus straminea (32.3%), the bearded-saki Chiropotes satanas chiropotes (50%) and the spider-monkey Ateles paniscus paniscus (2[1+]) from Balbina and in the squirrel-monkey Saimiri ustus (21%) and the black-faced-spider-monkey Ateles paniscus chamek (28.6%) from Samuel.

Cutaneous leishmaniasis in frequent in equines from an endemic area in Rio de Janeiro, Brazil

In an endemic area of cutaneous leishmaniasis in Rio de Janeiro State where a mule had been found infected, a systematic search among equines was performed, resulting in the detection of Leishmania parasites in skin lesions of 30.8% of the animals, which included horses and mules. The eventual role of equines in the epidemiology of the human disease is being investigated.

The neotype of anopheles albitarsis (Diptera: culicidae)

Anopheles albitarsis neotype is described from specimens collected in Baradero, Argentina, in Shannons trap, in horse and pig stables and on the progeny of engorded females. The description includes illustrations of adult female, male and female genitalias, scanning electron miscroscopy of the eggs and complete chaetotaxy of pupa and larva. The importance for electing a neotype is based on the realization that An. albitarsis is a complex of cryptic species. It is an attempt to provide typt-locality specimens with which other memebers of the group can be compared.

A cronologia da descoberta dos transmissores da malária na Amazônia brasileira

In the Amazon Region of Brazil, during the first three decades of this century, anophelines of the subgenus Nyssorhynchus not precisely identified to species were regarded as the probable malaria vectors. In 1931 and 1933 Anopheles darlingi, and in 1942-1946 An. aquasalis were confirmed as carriers, the former in the interior, the latter along the coast, because of their habits and salivary gland infection. An. albitarsis and An. braziliensis seemed to be occasional, secondary vectors. Forty years later, through immunological tests, other species are being pointed as naturally infected: An. triannulatus, An. nuneztovari, An. oswaldoi, An. strodei, An. galvaoi and An. peryassui. The importance of all incriminated species except An. darlingi (the main vector wherever present) and An. aquasalis has yet to be measured.

Are asian monkeys the original mammalian hosts of Trypanosoma conorhini

It is hypothesized that Asian monkeys were the original hosts of Trypanosoma conorhini because they have been found naturally infected, the vector among rats is a tropicopolitan triatomine bug that belongs to a complex of Asian species, and primates were shown to be more susceptible than rats.

Lutzomyia gasparviannai Martins, Godoy & Silva, 1962, probable vector of Leishmania mexicana ssp. in Viana municipality, Espírito Santo State, Brazil

Dos flebotomos atraidos pelo Proechimys iheringi numa area onde esse roedor foi achado naturalmente infectado por Leishmania mexicana ssp., 98,1% foram Lutzomyia gasparviannai, o que sugere que essa especie nao antropofilica seja o transmissor entre os roedores mas nao habitualmente ao homem.