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PubMed1978

Parasitological and ecological aspects of Schistosomiasis mansoni in the valley of the Paraíba do Sul River (São Paulo State, Brazil) I. Natural infection of small mammals with Schistosoma mansoni.

Small mammals naturally infected with Schistosoma mansoni were studied in the valley of the Paraíba do Sul river (São Paulo State, Brazil). 192 animals of 12 species were examined post mortem. Cavia aperea, Holochilus brasiliensis leucogaster, Nectomys squamipes squamipes, Oryzomys nigripes eliurus and Zygodontomys brachyurus were found infected. Most schistosome eggs found in the faeces were mature but no eggs were found in the faeces of C. aperea although adults were recovered. In the other infected animals the number of eggs per gram of faeces showed a marked daily variation. Perfusion of the portal system demonstrated that in H. b. leucogaster worms usually remained in the mesenteric veins. In C. aperea 75.7% of worms were found in the portal and intra-hepatic veins. H. b. leucogaster seems to be the rodent most likely to play a role in the epidemiology of schistosomiasis mansoni in the valley of the Paraíba do Sul river.

Animals↗
PubMed1982

Survival of Loa loa following transplantation from drills (Mandrillus leucophaeus) into jirds (Meriones unguiculatus): parasitology and pathology.

Two drills infected with Loa loa maintained a microfilaraemia for four and a half years ranging from less than 1 mf/100 microliters to 1150 mf/100 microliters. No significant tissue reactions to the adult worms were seen at autopsy. Adult worms were transplanted into the peritoneal cavities of naive jirds when a persistent microfilaraemia first developed by 17 days. Retransplantation of adult worms into naive jirds produced a microfilaraemia and microfilariae in the peritoneal cavities of three out of five animals. These three animals were all negative for circulating parasites by eight and a half months. The tissue reactions to the worms in the jirds are described, including a granulomatous response surrounding adults and a myositis involving microfilariae.

Animals↗
PubMed1983

Amoebiasis and giardiasis in Bangladesh: parasitological and serological studies.

To determine the prevalence of infections with Entamoeba histolytica and Giardia lamblia in Bangladesh, we screened stool specimens from patients with diarrhoea attending urban (N = 2,246) and a rural (N = 2,791) hospital and a group of healthy urban residents (N = 440). Sera from 200 healthy villagers were also examined for antibody to E. histolytica using the immunofluorescent antibody test. The prevalence of E. histolytica cysts or trophozoites in all groups assessed by examination of a single stool specimen ranged from 0% among infants (less than 1 year) to 34% among healthy adults 30 to 44 years old. G. lamblia was uncommon in infants and found most frequently in urban hospital patients aged five to nine (21%). 12% of one- to two-year-old children had serum antibody to E. histolytica at a titre of 1:40. By age 14 years, 80% of those tested were seropositive, and this prevalence declined thereafter with increasing age. Amoebiasis and giardiasis occur frequently in Bangladeshi populations and the morbidity and mortality associated with these infections need to be assessed.

Adolescent↗
PubMed1987

Repeated mass treatment of schistosomiasis mansoni: experience in hyperendemic areas of Brazil. I. Parasitological effects and morbidity.

The current project, carried out in Viçosa (state of Alagoas, Brazil), sought to assess the impact of repeated mass treatment campaigns (4 times over a period of 5 years) upon the prevalence, egg counts and morbidity of schistosomiasis mansoni. Results were not impressive. Some control seems to have been achieved in zones of the town better-off in terms of sanitation and socio-economic conditions, while in other areas no effect whatsoever of chemotherapy was detected. Neither resistance to the drug (oxamniquine) nor its deterioration could be held responsible, since a short-term follow-up of a group of children personally treated by the authors showed rapid reinfection, after an excellent initial response. This study, complemented by data from an area in Pernambuco and a hospital survey over the period 1978-84, indicated that morbidity due to schistosomiasis was decreasing, although there was some evidence that other factors may be at least partly responsible for the increasing scarcity of "hepatosplenic" schistosomiasis. Schistosomiasis, a strictly focal problem, thus calls for a targeted approach to control. It is believed that chemotherapy alone will not suffice and that sanitation, vector control and, perhaps, health education are equally essential in areas which remain refractory to mass treatment.

Adolescent↗
PubMed1987

The epidemiology of schistosomiasis in the later stages of a control programme based on chemotherapy: the Basrah study. 1. Descriptive epidemiology and parasitological results.

The association between infection with Schistosoma haematobium and various factors including water contact pattern, past history of haematuria and treatment for schistosomiasis and cercarial dermatitis was investigated in Southern Iraq. The study covered mainly primary schoolchildren in different areas of Basrah and in Al-maadan locality where the majority of households with infected schoolchildren occurred. Urine examination was by the sedimentation and Nuclepore filtration methods. S. haematobium infection was very focal in distribution. There was evidence of local transmission in the Al-maadan locality, while in Abu-al-Jawzi schistosomiasis might have been acquired from endemic areas outside Basrah governorate. Swimming, history of haematuria, and history of treatment of schistosomiasis were significantly associated with the level of infection determined by egg count. Cercarial dermatitis, and bathing, washing clothes and fetching water were not significantly associated. The prevalence of infection among male members of households of infected children was significantly higher than that among male members of the remaining households in Al-maadan. There was no evidence of clustering of cases at household level. The implications of these findings for control and for future research on schistosomiasis in Basrah are discussed.

Adolescent↗
PubMed1987

Parasitological evaluation of curative and subcurative doses of 9-acridanone-hydrazone drugs against Schistosoma mansoni in baboons, and observations on changes in serum levels of anti-egg antibodies detected by ELISA.

Derivatives in the class of 9-acridanone-hydrazones were found to be highly active against Schistosoma mansoni in baboons. Single doses of 25 mg/kg were fully effective. Data are presented showing changes detected by ELISA in antibody levels against schistosome eggs which correlated positively with the effect of chemotherapy. This approach may help to evaluate the effects of treatment of human schistosomiasis where the detection of low egg counts is problematic.

Acridines↗
PubMedDate not supplied

Loa loa and Mansonella perstans filariasis in the Chaillu mountains, Congo: parasitological prevalence.

1934 Bantus and 379 Pygmies were investigated for Loa loa and Mansonella perstans filariasis in 7 villages in the Chaillu forest of the Congo. Bantus were more frequently infected with L. loa than Pygmies (18.9% of microfilariae carriers compared with 10.6%). In individuals over 30 years of age, males were more frequently infected than females. Microfilarial densities increased until the age of 20 years and then remained stable. Parasite load was not significantly different in the two ethnic groups. For mansonelliasis, the microfilarial rate was higher in the Pygmies (67.5% compared with 22.0%) and males of the 2 groups were more frequently infected than females. Microfilarial load was also higher in Pygmies than in Bantus (mean microfilarial densities (MfD 50) 13 and 2 respectively). In the Pygmy group, MfD 50 for M. perstans increased with age whereas it remained stable in the Bantus. 53.8% of the 249 questioned persons had experienced worm migration under the conjunctiva. Both ethnic groups were equally exposed to the vectors of L. loa and reasons for the difference in prevalence of microfilaria carriers are discussed. For mansonelliasis increased contact with vectors may explain the higher degree of infestation observed in Pygmies. Other filariases were infrequent in (Mansonella streptocerca), or absent from (Onchocerca volvulus and Wuchereria bancrofti), the study area.

Adolescent↗
PubMed1989

Recent advances in the parasitology of malaria.

This review represents a highly personal view of only some of the advances made on the biology of malaria in the period 1986-1987. Progress has stemmed largely from new or refined techniques applied to the logical demonstration of eukaryotic principles; and more rarely from either new conceptual advances, or the revelation of critical differences in the biology of Plasmodium from that of other eukaryotes. Significant steps have been made in the recognition of the complexity of interaction between the parasite and both its vertebrate and invertebrate hosts. It is this very complexity of interaction which warns against the presumption that the successful application of any single control strategy is imminent.

Animals↗
PubMedDate not supplied

The clinical and parasitological presentation of Plasmodium falciparum malaria in Uganda is unaffected by HIV-1 infection.

The relation between Plasmodium falciparum malaria and symptomatic human immunodeficiency virus 1 (HIV-1) infection was investigated in paediatric and adult patients in Kampala, Uganda, from 1987 to 1989. Both infections contributed largely to hospital morbidity. Of 1527 clinically suspicious in-patients, 61% were positive for HIV-1 infection. 52% of patients with positive HIV-1 serology fulfilled the World Health Organization clinical case definition for acquired immune deficiency syndrome (AIDS) in Africa. No association could be found between HIV-1 infection and malaria either in paediatrics or in adults. P. falciparum parasitaemia was present in 18% of all patients and no differences in prevalence of malaria infection or in parasite density could be demonstrated between HIV-1 positive and HIV-1 negative patients. The comparison of clinical symptoms showed typical differences in AIDS-related morbidity but no difference in malaria-specific morbidity. Also, the response to malaria treatment was the same in HIV-1 positive and HIV-1 negative patients. P. falciparum malaria does not appear to act as an opportunistic agent in AIDS patients in Uganda.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

A community trial of ivermectin for onchocerciasis in Sierra Leone: clinical and parasitological responses to the initial dose.

A double-blind placebo-controlled trial of ivermectin was started in 1987 in 6 villages in southern Sierra Leone. 1625 villagers, 93% of the total population, were surveyed before treatment and allocated at random to the trial. Onchocerciasis was hyperendemic and of moderate intensity in the area. Typical onchocerciasis skin lesions were seen in most cases; the blindness rate was 1.5% and a further 4.3% had visual impairment. Six months after treatment 988 subjects (80%) were reassessed and microfilarial loads in the ivermectin group were found to be 10% of control levels. Additionally, blood eosinophil concentrations were reduced by one-quarter. The severity, but not the prevalence, of skin lesions was significantly reduced in the ivermectin group, with a particularly marked effect on papular eruptions. There had been no reduction in the prevalence of itching, nor had markers of general health shown improvement after ivermectin. Ivermectin is an effective microfilaricidal agent and may improve Onchocerca-related skin lesions after a single dose. However, the lack of obvious benefit to a target population after the first dose of ivermectin may reduce compliance with subsequent doses. This has implications for planned mass treatment initiatives in onchocerciasis endemic regions.

Animals↗
PubMedDate not supplied

Studies on the leishmaniases in the Sudan. 2. Clinical and parasitological studies on cutaneous leishmaniasis.

In the Omdurman Hospital for Tropical Diseases, Sudan, from 6 October to 1 December 1986, 736 patients with cutaneous leishmaniasis (CL) were studied. The duration of the lesions varied from a few days to 4 months, usually (56%) 1-3 months. Multiple lesions ranging from one to 50 (mean = 4) were present in 80% of cases. Ulcerative lesions were found in 44%, nodulo-ulcerative in 31%, nodular in 31% and others, including infiltrated, fungating and warty lesions, in 5% of patients. The lower limbs were involved in 66%, upper limbs in 50%, face in 6%, back in 4%, chest in 2%, abdomen in 1% and buttocks in 0.1%. Lesions were also found on the ear, scalp, genitalia and mucocutaneous junctions. Lymphatic involvement was present in 11% of the patients, secondary infection in 18%, fever in 17%, pain in 38% and itching in 61%; 3% of the patients were diabetics. Features of diffuse cutaneous leishmaniasis were noted in one patient and three cases presented with an 'id' reaction. A slit-skin smear was positive in 88% of the cases. Using thin-layer starch gel electrophoresis, 23 stocks from man and one from Arvicanthis niloticus were identified by the characterization of 12 enzymes as Leishmania major zymodeme LON-1. Various therapeutic regimens are discussed. Only patients with severe lesions (approximately 15%) were given 3 to 4 weeks' treatment with intravenous Pentostam, to which all except 2 responded satisfactorily with minimal side effects.

Adolescent↗
PubMedDate not supplied

Studies on the leishmaniases in the Sudan. 3. Clinical and parasitological studies on visceral and mucosal leishmaniasis.

The epidemiological, clinical and laboratory findings of 27 patients with visceral leishmaniasis (VL) and six with mucosal leishmaniasis (ML) in Sudan are described. The diagnosis was confirmed by the demonstration of amastigotes in bone-marrow in 20 cases with VL (80%) and impression smears in 2 cases with ML. The enzyme-linked immunosorbent assay and direct agglutination test were positive in all the sera tested. The leishmanin test was positive in all patients with ML, the diameter of the reaction ranging from 18 to 28 mm (mean 23 mm). Only one isolate (from a patient with VL) grew sufficiently well in culture to be typed and this was characterized by isoenzyme electrophoresis as Leishmania donovani zymodeme LON-46. The possibility that the ML isolate could have been L. major zymodeme LON-1 is discussed. The importance of further research to isolate and identify by biochemical procedures a more representative range of isolates of Leishmania from different clinical types in the Sudan, in order to elucidate questions such as the relationship between the vectors and possible animal reservoirs, is emphasized.

Adolescent↗
PubMedDate not supplied

Fever episodes in a holoendemic malaria area of Tanzania: parasitological and clinical findings and diagnostic aspects related to malaria.

All episodes of acute illness, in children aged 0-9 years, were registered during 3 years in a health clinic in a village of about 500 inhabitants in a malaria holoendemic area on the Tanzanian coast. Of 668 clinical episodes, 395 were diagnosed as malaria. There was no death. Only 5% of the children with malaria episodes came to the clinic after more than 3 d of symptoms. All 11 severe anaemias occurred among these children. Fever was reported in 98%, vomiting in 15%, and diarrhoea in 8% of the malaria episodes. Intermittent fever was reported in 98% of the malaria patients with more than one day of fever, compared to 4% of those with other febrile illnesses. Parasite densities > or = 10,000/microliters were found in 48% of the malaria episodes. Densities > or = 400/microliters were found in 96% of the malaria episodes and in only 8% of the other febrile illnesses. The 16 malaria episodes (4%) with densities below that level were all in children under one year of age. The ability of the rural medical aid or the doctor to differentiate malaria episodes from other febrile illnesses without microscopical examination was limited. Although very few malaria episodes were missed, substantial over-diagnosis resulted in specificity values of only 13% and 52% for their respective malaria diagnoses. It is concluded that intermittent fever was strongly associated with malaria, but a high accuracy of malaria diagnosis in febrile children requires microscopical examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗