Showing papers in "Transactions of The Royal Society of Tropical Medicine and Hygiene in 1993"

A malaria control trial using insecticide-treated bed nets and targeted chemoprophylaxis in a rural area of The Gambia, West Africa

Abstract: Background data on child mortality and morbidity from malaria were obtained in a new study area in the centre of The Gambia, south of the river, chosen as the site for a malaria intervention trial. Infant and child mortality rates were 120 and 41 per 1000 respectively. Results obtained using post-mortem questionnaires suggested that malaria was an uncommon cause of death in children under the age of one year but responsible for about 40% of deaths in children aged 1–4 years. Ninety-two percent of deaths attributed to malaria occurred during or immediately after the rainy season. Parasite and spleen rates in children aged 1–5 years at the end of the malaria transmission season were 66% and 64% respectively. Malariometric indices were similar in primary health care (PHC) villages, selected as sites for an intervention with insecticide-treated bed nets and targeted chemoprophylaxis, and in smaller, non-PHC, control villages.

The rapid manual ParaSight®-F test. A new diagnostic tool for Plasmodium falciparum infection

Abstract: A rapid manual test for Plasmodium falciparum, the ParaSight-F test, has been used on a series of patients in a holoendemic malaria area of coastal Tanzania. The test, which is an antigen capture test detecting trophozoite-derived histidine rich protein-II, is simple to perform and provides a definitive answer in about 10 min. It requires no special equipment and is read using a single drop of blood. When compared with 272 thick blood films examined microscopically by 2 observers and confirmed by the QBC malaria test, the ParaSight-F test had 88.9% sensitivity and 87.5% specificity. Detectable antigenaemia in a group of 40 people declined following treatment with Fansidar and by 10 d after treatment all but 4 individuals were antigen free. The remaining 4, although clear of peripheral parasitaemia, remained antigenaemic for 14 d. The test shows great promise for rapid effective diagnosis of P. falciparum in clinics and village health centres where there is no facility for microscopy. Because of its accuracy and rapid action it may even obviate the need for microscopical examination of blood films to diagnose P. falciparum malaria.

Overlap in the clinical features of pneumonia and malaria in African children

Abstract: Pneumonia and malaria are common causes of childhood morbidity and mortality in many developing countries and simple guidelines have been proposed to facilitate their diagnosis by relatively unskilled health workers. We have studied children in The Gambia attending out-patient and under-five clinics with clinically suspected pneumonia (cough or difficulty in breathing and a raised respiratory rate) during periods of high or low malaria transmission. During a period of high malaria transmission, 33% of these children had radiological evidence of pneumonia (with or without malaria parasitaemia) compared to 38% who had malaria parasitaemia, no radiological evidence of pneumonia and no other obvious cause of fever. Corresponding figures during a period of low malaria transmission were 48% and 6% respectively. The clinical overlap between pneumonia and malaria has important implications for case management strategies and evaluation of disease-specific interventions in regions in which both pneumonia and malaria are prevalent.

Treatment of Plasmodium falciparum malaria with pyrimethamine-sulfadoxine : selective pressure for resistance is a function of long elimination half-life

Abstract: In an area of continuing transmission of Plasmodium falciparum on the Kenya coast, children treated with pyrimethamine-sulfadoxine experienced rapid parasite clearance, although a high proportion became reinfected within a short time. The frequency of pyrimethamine resistance in vitro in new infections was higher during the elimination phase of drug from a previous treatment. In infections which occurred at times when predicted residual drug concentrations were no longer inhibitory, incidence of pyrimethamine resistance was no different from the natural or background frequency. These results are discussed in terms of the selective pressure for resistance which is exerted by drugs with long elimination half-lives and a consideration of possible ways by which the problem might be addressed.

The clinical and immunological spectrum of American cutaneous leishmaniasis

Abstract: American cutaneous leishmaniasis is characterized by a spectrum of clinical manifestations. These include localized, often self-healing single lesions, intermediate forms which frequently produce mucosal lesions and often show exaggerated delayed-type hypersensitivity (DTH), and the rare diffuse cutaneous leishmaniasis in which no reaction of protective cell-mediated immunity or DTH can be demonstrated. Clinical, pathological and immunological studies have begun to unravel some of the mechanisms associated with different disease manifestations, dependent on complex interactions between the host immune response, measured in terms of indices including lymphocyte subsets and lymphokines in vitro and within active lesions, and different species of Leishmania.

The importance of sensitive detection of malaria parasites in the human and insect hosts in epidemiological studies, as shown by the analysis of field samples from Guinea Bissau

Abstract: A method based on the polymerase chain reaction (PCR) for highly sensitive detection and identification of human malaria parasites was applied to blood and mosquito samples obtained from a village in Guinea Bissau. The prevalence of parasites in the human population was shown to be greatly underestimated by microscopical examination. In particular, a high incidence of Plasmodium malariae and P. ovale parasites was revealed only by the PCR assay. Preliminary evidence was obtained to show that the distribution of P. malariae infections within the village was non-random. This was supported by analysis of the parasite species infecting the mosquito vector. The implication of these results for the design and interpretation of epidemiological surveys is discussed.

Bed nets for the prevention of malaria and anaemia in pregnancy.

Abstract: A prospective comparison of the antimalarial efficacy of bed nets was conducted with 341 pregnant women living in a mesoendemic malarious area of the Thai-Burmese border. Women in 3 adjacent study sites were allocated at random to receive either a single size permethrin-impregnated bed net (PIB), a non-impregnated bed net (NIB), or to a control group who used either their own family size non-impregnated bed net (FNIB) or no net. In one study site, but not the other 2, PIB significantly reduced parasite densities and, together with FNIB, reduced the incidence of malaria in pregnancy from 56% to 33% (relative risk = 1.67, confidence interval = 1.07-2.61, P = 0.03, allowing for parity). Anaemia proved a more sensitive marker of bed net antimalarial efficacy than parasite rates. The incidence of anaemia (haematocrit < 30%) at all study sites was significantly lower at delivery in the PIB (27%) and FNIB groups (21%) than in the NIB group (41%) or those using no net (56%). This suggests that a significant proportion of the malaria in pregnancy in this mesoendemic area was sub-patent. Both patent Plasmodium falciparum parasitaemia and anaemia were associated with a reduction in birth weight. Infant mortality was high (16%) and strongly associated with prematurity, low birth weight and maternal anaemia. PIB were well tolerated and had no apparent adverse effect on the pregnancy or infant development. Although the overall effect of bed nets on patent parasitaemia was marginal, they were associated with a significant reduction in maternal malaria-associated anaemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation of the stage of parasite development in the peripheral blood to prognosis in severe falciparum malaria

Abstract: Admission blood films from 72 patients who died of severe falciparum malaria (50 Thai adults, 22 Gambian children) were matched retrospectively for parasitaemia with equal numbers of survivors. The peripheral blood parasites from fatal cases were more mature than those from survivors. Tiny rings (TR) comprised > 50% of parasites in 47/72 (65%) survivors but only 12/72 (17%) of fatal cases (P 10(4) MTS/microL, 30 (81%) died. These findings were confirmed in a prospective study of 279 adult Thai patients admitted sequentially with acute falciparum malaria. Only 4 of the 19 fatal cases (21%) had > 50% TR, compared with 130 of 260 (50%) survivors, whereas > 20% MTS were found in 10/19 (53%) fatal cases, compared with 28/108 (27%) severe malaria survivors, and 26/155 (17%) patients with moderately severe malaria (P = 0.001). As a predictor of fatal outcome, the finding of either > 10(4) MTS/microL or > 5 x 10(5) parasites/microL in severe malaria had a sensitivity of 90% (95% confidence interval [CI] = 75-97%) and a specificity of 72% (95% CI = 59-86%). These observations are consistent with the hypothesis that a predominance of mature parasites in the peripheral blood reflects a greater sequestered biomass, and thus more severe disease. Simple microscopical assessment of parasite maturity on an admission blood slide provides important pathophysiological and prognostic information in severe falciparum malaria.

Periodicity and space-time clustering of severe childhood malaria on the coast of Kenya

Abstract: Traditionally malaria epidemiology has focused on factors such as parasite rates and vector dynamics without specific reference to disease. There are limited comprehensive data on malaria as a life-threatening event in African children. We have identified, through hospital surveillance, 581 episodes of severe malaria in residents of a defined area on the Kenya coast over a period of 3 years. This represents an absolute minimum risk of developing severe malaria by the fifth birthday of 1 in 15. The presentation of severe malaria showed marked seasonality, but the timing and magnitude of these fluctuations varied considerably between years. A satellite navigational system was used to define the exact location of the home of each severe malaria case. Space-time clustering of severe malaria was evident in this community. Seasonal peaks in incidence of severe malaria may comprise discrete mini-epidemics. In contrast, parasite rates in the community varied little during the course of the surveillance. The monitoring of disease, as opposed to parasitization, in children may result in more effective targeting of intervention resources.

A malaria control trial using insecticide-treated bed nets and targeted chemoprophylaxis in a rural area of The Gambia, West Africa: 6. The impact of the interventions on mortality and morbidity from malaria

Abstract: The effects of insecticide-impregnated bed nets on mortality and morbidity from malaria have been investigated during one malaria transmission season in a group of rural Gambian children aged 6 months to 5 years. Sleeping under impregnated nets was associated with an overall reduction in mortality of about 60% in children aged 1–4 years. Mortality was not reduced further by chemoprophylaxis with Maloprim ® given weekly by village health workers throughout the rainy season. Episodes of fever associated with malaria parasitaemia were reduced by 45% among children who slept under impregnated nets. The addition of chemoprophylaxis provided substantial additional benefit against clinical attacks of malaria; 158 episodes were recorded among 946 children who slept under impregnated nets but who also received chemoprophylaxis. Chemoprophylaxis reduced the prevalence of splenomegaly and parasitaemia at the end of the malaria transmission season by 63% and 83% respectively. Thus, insecticide-impregnated bed nets provided significant protection in children against overall mortality, mortality attributed to malaria, clinical attacks of malaria, and malaria infection. The addition of chemoprophylaxis provided substantial additional protection against clinical attacks of malaria and malaria infection but not against death.

Lytic antibody titre as a means of assessing cure after treatment of Chagas disease: a 10 years follow-up study.

Abstract: A complement-mediated lysis test (CoML) using living trypomastigotes was compared with conventional serological methods and with haemoculture. Over a 10 years follow-up period evidence was obtained which supported the view that chagasic patients, treated with nitroheterocyclic drugs, in whom CoML had reverted to negative, might be considered cured despite conventional serology remaining positive.

Albendazole as a treatment for infections with Giardia duodenalis in children in Bangladesh

Abstract: Albendazole, a broad spectrum anthelmintic recently shown to be active in vitro against Giardia duodenalis, was given at 4 different dosages and compared with metronidazole in the treatment of children in Bangladesh infected with Giardia. Three stools were collected over 10 d after treatment and examined microscopically. Albendazole was found to be effective: single doses of either 600 mg (n = 103) or 800 mg (n = 114) successfully treated 62% and 75% of infections, respectively; 400 mg given either once a day for 3 d (n = 116) or for 5 d (n = 115) successfully treated 81% and 95% of all infections, respectively. Albendazole given daily at 400 mg for 5 d was as effective as metronidazole, which cured 97% of infections (n = 230). Albendazole may thus be an alternative treatment for infections with Giardia, while the moderate efficacy of single doses may provide a benefit in addition to its effects on several species of intestinal helminths.

A malaria control trial using insecticide-treated bed nets and targeted chemoprophylaxis in a rural area of The Gambia, West Africa 3. Entomological characteristics of the study area

Abstract: Baseline entomological surveillance was carried out in a rural area of The Gambia during the rainy season in 1988, one year before the implementation of a malaria control programme using insecticide-impregnated nets and targeted chemoprophylaxis in villages with a primary health care (PHC) system. Mosquito collections took place in 6 pairs of settlements each with untreated bed nets; within each pair there was a large PHC village with a resident village health worker (VHW) and traditional birth attendant (TBA) and a smaller non-PHC village without either a VHW or a TBA. The most common vectors in the study area were Anopheles gambiae sensu stricto and, to a lesser extent, An. arabiensis. These mosquitoes were found in appreciable numbers for at least 4 months of the year (geometric mean/bedroom/night = 32.5, 95% confidence interval 18.2–57.3). Numbers of mosquitoes collected in PHC villages or non-PHC villages were not significantly different. Greater numbers of mosquitoes were found in villages closer to the River Gambia than in those further away. Evidence for DDT resistance due to elevated glutathione S-transferase activity was found in one of the 12 villages, but there was no evidence of resistance to organophosphate or carbamate insecticides as suggested by the low esterase levels and carbamate sensitive acetylcholinesterase.

Yellow fever vaccination and pregnancy: a four-year prospective study

Abstract: During an outbreak of yellow fever (YF) in Nigeria in 1986-1987, women at various stages of pregnancy were vaccinated against YF, either because those pregnancies were not known at the time or because they requested vaccination out of fear of acquiring the disease. This offered an opportunity to assess the safety and efficacy of YF vaccine in pregnant women and the effect of this vaccine on their newborn children. Pre-vaccination and post-vaccination serum samples from the vaccinated pregnant women were tested by enzyme-linked immunosorbent assay and by neutralization tests for antibody to YF virus. The results showed that the antibody responses of these pregnant women were much lower than those of YF-vaccinated, non-pregnant women in a comparable control group. Follow-up of these women and their newborn children for 3-4 years showed no abnormal effect that could be attributed to the YF vaccine, which suggests that vaccination of pregnant women, particularly during a YF epidemic, may not be contraindicated.

Mortality and morbidity from malaria in the study area

Abstract: Background data on child mortality and morbidity from malaria were obtained in a new study area in the centre of The Gambia, south of the river, chosen as the site for a malaria intervention trial. Infant and child mortality rates were 120 and 41 per 1000 respectively. Results obtained using post-mortem questionnaires suggested that malaria was an uncommon cause of death in children under the age of one year but responsible for about 40% of deaths in children aged 1-4 years. Ninety-two percent of deaths attributed to malaria occurred during or immediately after the rainy season. Parasite and spleen rates in children aged 1-5 years at the end of the malaria transmission season were 66% and 64% respectively

Epidemiology of Buruli ulcer in Amansie West district, Ghana

Abstract: This paper describes 90 cases of Buruli ulcer in Amansie West district, Ghana. 49% were below 15 years of age while 20% were over 50 years. There was a significant difference in the age and sex composition, with more males among the younger age groups than females but the converse among adults. Seasonal variation is described, with peak incidence in September and October. Cases who had received bacillus Calmette-Guerin (BCG) vaccination had a shorter duration of the ulcer than those who were not vaccinated. No such association was found between BCG vaccination and the age of onset of the disease. There was no significant difference between cases and controls regarding their BCG vaccination status. There is an urgent need to regard Buruli ulcer in Ghana more seriously.

A malaria control trial using insecticide-treated bed nets and targeted chemoprophylaxis in a rural area of The Gambia, West Africa 4. Perceptions of the causes of malaria and of its treatment and prevention in the study area

Abstract: Perceptions of the causes of malaria, its treatment and prevention were studied among 996 adults, selected randomly from 73 villages and hamlets in a rural area of The Gambia. Structured questionnaires and other interview techniques were used for data collection. Malaria has no specific name in the study area; it is referred to commonly as Fula kajewo (Fula fever). Only 28% of the respondents knew that mosquitoes transmitted malaria. However, most people believed correctly that August to October was the main malaria season. Eighty-six per cent of the subjects were bed net users. The majority of nets were produced locally, usually white in colour and made of sheeting fabrics. Usage of nets was correlated with ethnic group, age and polygamy but not with education, income, occupation or ownership of certain items which indicate high social status. Analysis of expenditure on mosquito coils indicated that non-users of nets spent 43% more on coils than did users. Bed nets have been used for a long time in the study area; 98% of users saw their parents using them during their childhood.

Compliance and absenteeism in school children: implications for helminth control.

Abstract: The validity of epidemiological surveys and the success of helminth control programmes based on the diagnosis of infection depend upon an accurate screening procedure. The success of all school-based control programmes, whether they involve prior diagnosis or not, depends on the level of school attendance and school enrolment. The degree to which compliance and school absenteeism may affect estimates of helminth infection and the coverage of treatment was investigated using empirical data from a survey conducted in 3 rural schools in Jamaica. Two sequential stool samples were requested from each child aged 9 to 12 years and screened for the presence and intensity of helminth infection using the Kato thick smear technique. Of the 696 children recruited into the study, 94% agreed to participate but only 90% of these children actually provided a stool sample for diagnosis and only 74% returned the second stool. Children infected with moderate to heavy loads of Trichuris trichiura were less likely to comply fully with the protocol than the uninfected children. They also took longer to comply and were absent from school more often than their uninfected counterparts. Increasing the sampling effort increased the compliance of all infected, and heavily infected, children. By giving them the option to comply, heavily infected children were under-represented by the sampling procedure. This has important implications for the design of control programmes and epidemiological surveys.

A malaria control trial using insecticide-treated bed nets and targeted chemoprophylaxis in a rural area of The Gambia, west Africa. 7. Impact of permethrin-impregnated bed nets on malaria vectors.

Abstract: The impact of permethrin-impregnated bed nets on malaria vectors was studied in 6 pairs of villages during the rainy season in 1989. In each pair, the residents of one village had their nets treated whilst those of the other remained untreated. Routine collections of mosquitoes were made outdoors in the early evening using human-biting collections, and indoors with insecticide sprays, light traps and by searches under bed nets. Mosquitoes of the Anopheles gambiae complex, An. gambiae sensu stricto, An. arabiensis and An. melas, were present in large numbers for 5 months of the study period. These mosquitoes were susceptible to permethrin as judged by bioassay results. Outdoor human-biting rates in the early evening in communities with treated bed nets were similar to those in communities with untreated nets. In villages with treated bed nets most biting occurred outdoors in the early evening with little taking place under impregnated nets. The insecticidal activity of permethrin-impregnated bed nets, dipped by the local population, provided good individual protection against mosquitoes throughout the rainy season and bed nets remained effective even when washed up to 3 times. There was little to suggest that the use of insecticide-treated nets reduced the survival of mosquito populations in villages with impregnated nets. The absence of the expected village-wide effects of net impregnation may have resulted from the circulation of mosquitoes between villages with treated and untreated nets. The proportion of mosquitoes which fed on humans did not differ significantly between villages with treated and untreated nets. Permethrin-impregnated bed nets proved an effective barrier against vectors when people were under their nets, but had no apparent effect on biting outdoors before individuals retired to bed.

A malaria control trial using insecticide-treated bed nets and targeted chemoprophylaxis in a rural area of The Gambia, west Africa. 5. Design and implementation of the trial.

Abstract: A large-scale malaria intervention programme using insecticide-treated bed nets and chemoprophylaxis administered to children was introduced into a rural area of The Gambia. The operation was carried out using the existing primary health care (PHC) service in the region. Training of the village health workers, sensitization of the communities, and implementation of net impregnation and the drug delivery programme are described. This delivery system resulted in over 90% of nets being treated with insecticide and 80% of children receiving over 90% of their tablets during the rainy season. There was considerable variation in the distribution of permethrin on a bed net and between individual nets, which is likely to facilitate the spread of insecticide resistance in the local mosquito populations. Bed nets made from heavier fabrics tended to absorb more insecticide than those made from lighter materials. Four months after dipping, 89% of the insecticide had been lost from treated nets. This was probably due mainly to women washing their nets, an activity carried out on average once every 2 months during the rainy season. The high number of insecticide-treated bed nets in the study area demonstrated that a malaria control programme operated through a PHC system can be implemented successfully.

Effect of a community-based Aedes aegypti control programme on mosquito larval production sites in El Progreso, Honduras

Abstract: This paper describes the results of a trial to assess the efficacy in reducing the density of larval production sites of utilizing community involvement in the planning and implementation of an Aedes aegypti control programme, in a dengue-endemic city in Honduras. In addition to a substantial increase in knowledge about dengue transmission and prevention, a relative reduction in Ae. aegypti larval infestation indices was found in those city neighbourhoods where community involvement was utilized compared with their untreated counterparts. Several methods of improving the impact of this type of programme are discussed.

Immunodiagnosis of Strongyloides stercoralis infection: a method for increasing the specificity of the indirect ELISA

Abstract: Indirect enzyme-linked immunosorbent assay (ELISA) allows sensitive detection of serum immunoglobulin (Ig) G against a soluble extract of Strongyloides stercoralis infective larvae. In this study, 40/40 (100%) human strongyloidiasis sera had high levels of anti-S. stercoralis IgG, but 30/40 (75%) filariasis sera, and 12/40 (30%) necatoriasis sera also had higher levels than control sera from UK residents. In attempts to increase the assay specificity by absorption of cross-reactive IgG, the effectiveness of pre-incubation of sera with extracts of different parasitic nematodes was investigated. One hour of incubation with 20 micrograms/ml aqueous extract of Onchocerca gutturosa absorbed cross-reactive IgG in most filariasis and necatoriasis sera, reducing the proportion with IgG levels above the positivity threshold by more than one-half. Preliminary results suggest that absorption with extracts of other filarial nematodes is equally effective, and that some of the cross-reactive IgG is directed against phosphorylcholine. Cross-reactive IgG in most necatoriasis sera was effectively absorbed with 20 micrograms/ml extract of Necator americanus. Cross-reactive IgG was not effectively absorbed with an extract of Ascaris lumbricoides. Absorption of cross-reactive IgG is an effective means of increasing the specificity of the indirect ELISA, for use in the immunodiagnosis and immuno-epidemiology of S. stercoralis infection.

Anophelines in the state of Acre, Brazil, infected with Plasmodium falciparum, P. vivax, the variant P. vivax VK247 and P. malariae

Abstract: Anophelines collected indoors and in the peri-domiciliary area in 3 localities in the Amazon region, state of Acre, Brazil, from August 1990 to January 1991 were examined by enzyme-linked immunosorbent assay (ELISA) using specific monoclonal antibodies directed against the repeats of the circumsporozoite proteins of Plasmodium falciparum, P. vivax, P. vivax V247, and P. malariae. Of the 3056 specimens collected, 2610 were Anopheles oswaldoi, 362 A. deaneorum, 60 A. triannulatus and 24 were A. darlingi. The infection rates of A. oswaldoi were 3.41% for P. falciparum, 2.26% for P. vivax, 1.22 for P. vivax VK247, and 0.42% for P. malariae. For A. deaneorum, the infection rates were 2.76% for P. falciparum, 0.55% for P. vivax, and 0.82% for P. vivax VK247. All samples of the other 2 species collected (A. triannulatus and A. darlingi) were negative in the ELISA. There were certain differences in the anopheline distribution and infection rates between these localities, and in one only A. oswaldoi was found to be infected. These results strongly point to A. oswaldoi as the main malaria vector in the region. No difference was found between the potential vectors of P. vivax and P. vivax VK247. The significance of these findings for malaria control is discussed.

A malaria control trial using insecticide-treated bed nets and targeted chemoprophylaxis in a rural area of The Gambia, West Africa: 1. A review of the epidemiology and control of malaria in The Gambia, West Africa

Abstract: Malaria was recognized as an important cause of death among early European visitors to The Gambia, but the infection was first studied systematically in the local population only in the 1950s. Studies undertaken in the village of Keneba at that time showed that nearly all children under the age of 5 years had parasitaemia throughout the year. More recent surveys in rural areas of The Gambia have shown much lower levels of parasitaemia, probably as a result of a decline in rainfall in The Gambia during the past 30 years and because of an increase in the availability of anti-malarial drugs. Nevertheless, community surveys and reviews of hospital statistics show that malaria is still one of the most important causes of death among Gambian children; about 1 in 25 rural Gambian children die from malaria before reaching the age of 5 years. Until recently, malaria control in The Gambia relied upon prompt treatment of clinical attacks, first with quinine and more recently with chloroquine, and upon some limited vector control in the capital, Banjul. However, during the past few years, it has been shown that mortality in rural children can be reduced substantially by means of chemoprophylaxis given by village health workers. Bed nets (mosquito nets) are used widely in The Gambia and epidemiological surveys have shown an association between the use of bed nets and protection against malaria. This observation led to a series of small scale intervention trials. These showed that conventional bed nets were not very effective at protecting against clinical attacks of malaria in children but that their protective effect was enhanced substantially when they were impregnated with the insecticide permethrin. The success of these pilot trials led to a much larger study of impregnated bed nets which had the objectives of determining whether the use of impregnated bed nets could reduce mortality in Gambian children and whether impregnation of bed nets could be accomplished successfully on a large scale through the national primary health care programme.

Serodiagnosis of alveolar hydatid disease by western blotting.

Abstract: The purpose of this study was to identify species-specific protein components of Echinococcus multilocularis by Western blotting and establish a simple and highly sensitive method for differential serodiagnosis of alveolar hydatid disease (AHD) from cystic hydatid disease Using Western blotting analyses we demonstrated 2 previously undescribed, species-specific, antigenic components of protoscoleces of E multilocularis easily detectable with sera from active AHD patients exclusively The 18 kDa component was recognized by sera from all active AHD patients, whereas the 16 kDa antigen was characteristically detected by patients with advanced lesions The potential utility of these components for differential serodiagnosis of AHD is discussed