ECHINOSTOMA LUISREYI N. SP. (PLATYHELMINTHES: DIGENEA) BY LIGHT AND SCANNING ELECTRON MICROSCOPY

The entire life cycle of the Brazilian Echinostoma luisreyi n. sp., of the 37-collar spine E. revolutum group, has been observed under experimental conditions. The snail Physa marmorata serves as its first natural intermediate host. This species and the planorbid Biomplalaria glabrata act as experimental second intermediate hosts. The worm recovery rate was 51.3 and 0.6% for mice and hamsters, respectively, but the infection did not develop in the quail Coturnix coturnix. The natural vertebrate host is not known. The most important morphological character of the new species separating it from the other Echinostoma species studied is the oral corner spines that increase in size from the latero-oral to the ventro-oral regions. The ratio of the sizes of the smaller oral spines and the larger aboral ones was 1.7:1.0. Also, the excretory pore is radially wrinkled and dorsally subterminal. Images obtained by scanning electron microscopy confirmed the characters that differentiate the new species and the most closely related species.

Biological aspects of a new isolate of Echinostoma paraensei (Trematoda: Echinostomatidae): susceptibility of sympatric snails and the natural vertebrate host

A new isolate of Echinostoma paraensei (Lie & Basch, 1967) was obtained from a natural vertebrate host, the water rat Nectomys squamipes. Relationships with sympatric snails, Biomphalaria glabrata; Physa marmorata and Lymnaea columella, as well as allopatric snails and the definitive hosts N. squamipes, Mus musculus, Rattus norvegicus, Mesocricetus auratus and birds were investigated. E. paraensei developed in all sympatric snail species following exposure to one or five miracidia. P. marmorata showed the highest infection rate (34% and 36%) followed by L. columella (18% and 24%) and B. glabrata (8% and 28%), respectively. Mortality was elevated in the patent period, with L. columella having the highest values. B. glabrata, P. marmorata, and L. columella did not differ in relation to cercarial encystment, and metacercariae from each species were able to infect N. squamipes with similar worm burdens. Recovered adult worms were found in clusters from the first to third sections of the small intestine. Miracidia of E. paraensei hatched after 10 days incubation in darkness in dechlorinated water at 28+/-1 micro C. Miracidia began to hatch 1 h after exposure to incandescent light.

Susceptibility of Nectomys rattus (Pelzen, 1883) to experimental infection with Schistosoma mansoni (Sambon, 1907): a potential reservoir in Brazil

The aim of the present research was to evaluate the potential of Nectomys rattus, the "water rat", to develop Schistosoma mansoni infection. Comparison with N. squamipes was carried out. Both species of rodents were submitted to transcutaneous infection using different infective cercariae loads: 50, 100 or 500. N. rattus showed high susceptibility to S. mansoni, with an infection rate of 71%. Rodents were able to excrete viable eggs of S. mansoni in the faeces during all infection period. For both species, the small intestine, followed by the liver and the large intestine, presented the highest concentration of eggs among the surveyed organs. Infection caused no animal death. Moreover, N. rattus accomplished the parasite's life cycle, by infecting the snails Biomphalaria glabrata and later Mus musculus. These evidences indicate that both N. rattus, as for N. squamipes are potential reservoirs for schistosomiasis in Brazil. Considering the fact that N. rattus and N. squamipes exist in the same natural ecosystems of S. mansoni, we suggest that these rodents must be regarded as influential factors in epidemiology surveys.

[Breastfeeding indicators in the city of Feira de Santana, Bahia, Brazil]

OBJECTIVE: To evaluate breast-feeding indicators surveying current alimentary status of under- two-year-old children.METHODS: During Vaccinations day, on June 15th, 1996, 3,898 mothers were interviewed in urban areas of Feira de Santana, Bahia, Brazil. The methodology proposed at WHO/CED/SER 91.14 was used. Rates were calculated for the appropriate age groups: breast-feeding exclusive and predominant, persistence of breast-feeding one and two years, median duration of breast-feeding, timely complemented breast-feeding, bottle-feeding and pacifiers utilization.RESULTS: The main results were exclusive breastfeeding rate of 45.6%, in children from 0-3 months old; breastfeeding medium duration of 9 months; and persistence of 45.4% of breastfeeding in children from 12-15 months old. CONCLUSIONS: These results pointed that children in Feira de Santana are benefitting from breast-feeding more than in other areas of Bahia and other states of the Brazilian Northeast reflecting correct orientation. The methodology revealed ease to applicate providing significant and replicable samples. Wider utilization of standardized methodologies will contribute to improve monitoring of breast-feeding indicators in Brazil.

Esophageal involvement in congenital Chagas' disease. Report of a case with megaesophagus

A full-term infant developed dysphagia, vomiting, and regurgitation immediately after birth. On examination at 5 months of age, he was malnourished and had radiographically proven megaesophagus. On direct examination his blood was positive for Trypanosoma cruzi. Additionally an enzyme immunoassay for T. cruzi IgM antibodies was positive. He underwent corrective surgery for the megaesophagus but died post-operatively of aspiration pneumonia. At autopsy, the esophagus was markedly dilated. There was an extreme reduction of neurons in Auerbach's plexus, and inflammation of this plexus and the muscular layer of the esophagus. Nests of parasites were seen in the esophagus and bladder. It is suggested that this patient was not in the chronic phase of Chagas' disease but represents an acute digestive phase of this infection. This is the fourth case in the literature of congenital Chagas' disease with esophageal involvement and clinical signs, and the first in which megaesophagus was seen grossly at post-mortem examination.