Concurrent infections and socioeconomic determinants of geohelminth infection: a community study of schoolchildren in periurban Guinea-Bissau.

We explored the association between subclinical intestinal helminth infections and other gastrointestinal pathogens in 706 schoolchildren from a poor semirural area while adjusting for socioeconomic risk factors. The study was carried out in two neighbouring areas in the capital of Guinea-Bissau in West Africa. Children aged 4-12 years were visited and one child per mother was invited to participate in the study. Among the 706 children included in the study, helminths were detected in 44.2%, enteropathogenic bacteria in 13.7%, protozoans in 51.1% and rotavirus in 5.9%. A total of 76.1% had an infection of some sort and 41.8% were concomitantly infected with more than one and up to five gastrointestinal pathogens. After adjustment for possible confounding factors, infection with helminths and Entamoeba histolytica/E. dispar remained associated. Other risk factors for helminths included increasing age, male gender, small mid-upper arm circumference and chicken husbandry. Maternal school attendance and belonging to a Muslim family were associated with a lower prevalence of helminths. Investigations of concomitant infections are valuable as they may have implications for control and treatment strategies.

Eosinophil cationic protein, soluble egg antigen, circulating anodic antigen, and egg excretion in male urogenital schistosomiasis.

Markers of male genital schistosomiasis (MGS) are needed to elucidate the consequences for reproductive health. Eosinophil cationic protein (ECP) and soluble egg antigen (SEA) in urine and semen, and circulating anodic antigen (CAA) in serum were assessed as MGS markers. Egg counts, ECP, and SEA in urine and CAA in serum, correlated positively. Seminal egg excretion exhibited marked day-to-day variations, but counts correlated positively with urinary egg counts and SEA in semen and with CAA. Positive predictive values with reference to seminal egg excretion were as follows: seminal ECP (52%), seminal SEA (83%), CAA (97%), and urinary egg excretion (82%). SEA in semen and CAA in serum constitute potential markers of MGS. However, urine egg counts as an indirect marker of MGS remains the preferred diagnostic method from a public health perspective.

Local perceptions and practices in regard to opisthorchiasis in two villages in Lao PDR.

The aim of the present study was to assess local perceptions and practices in regard to opisthorchiasis in a village receiving treatment and health education compared to a village where no intervention was offered. The study was conducted two years after a health education campaign had been carried out. Focus group discussions and semi-structured interviews were performed among 68 men and women. The results of the study show there were distinct differences in perceptions about opisthorchiasis when comparing the two villages. It appears that introducing health education alongside treatment does have an effect on knowledge and change in behavior. Eating raw fish was mainly practiced by men, however women were not aware they were exposed to opisthorchiasis while preparing food. Although there is no locally derived term, a medically appointed term for opisthorchiasis was acknowledged. Due to the vague disease symptoms, no treatment seeking behavior was found in relation to the disease. Further studies are needed to shed light on gender differences in regard to eating behavior and to assess infection risk among different Lao dishes containing freshwater fish.

Treatment and reinfection of water buffaloes and cattle infected with Schistosoma japonicum in Yangtze River Valley, Anhui province, China.

The aim of the present study was to evaluate the efficacy of praziquantel treatment of Schistosoma japonicum infections in cattle and water buffaloes and to assess the natural rate of reinfection after treatment. The studies were conducted on 2 islands in the Yangtze River, Anhui province, China, from March 2003 to January 2004. The efficacy of praziquantel was 97% when applied orally wrapped in tree leaves at the recommended doses. The efficacy was measured using a miracidium hatching technique on fecal samples collected 20 days after treatment. The treatment did not give rise to any major side effects. Reinfection after treatment was high and occurred throughout the year in both cattle and water buffaloes. Age-related resistance was only observed in water buffaloes. It is concluded that although praziquantel is highly effective against S. japonicum in cattle and water buffaloes, a single annual treatment strategy does not effectively control transmission. New strategies for integrated control of animal schistosomiasis are needed to control schistosomiasis transmission more effectively in farm areas of China.

Schistosoma japonicum eggs survive passage through dogs and chickens.

The present study sought to elucidate whether Schistosoma japonicum eggs could survive a passage through dogs and chickens. Three dogs and three chickens were used for the experiment. The dogs were allowed to eat goat faeces containing 80 S. japonicum eggs per gram. The chickens were given 2 ml of water containing more than 100 S. japonicum eggs per ml. The hatchability of the eggs was 51.8% prior to administration. All faeces were collected for 3 days from the dogs and for 2 days from the chickens and egg excretion and hatchability were measured. The results showed that nearly 50% of the eggs administered to the dogs were recovered in the faeces during the first 2 days and during the first 25 h 39% of the recovered eggs were viable and able to hatch. In the chickens 9% of the administered eggs were recovered within 27 h and within the first 3.5 h after administration 19% of the recovered eggs were viable and able to hatch. The results suggest that both dogs and chickens may act as transport hosts for S. japonicum in endemic areas.

Transmission of Schistosoma japonicum by humans and domestic animals in the Yangtze River valley, Anhui province, China.

The aim of the present work was to assess the relative contribution to transmission of Schistosoma japonicum by humans and domestic animals in two villages in the Yangtze River valley in Anhui province, China. A cross-sectional survey was conducted to determine the prevalence and intensity of S. japonicum in humans, cattle, water buffaloes, horses, pigs, goats, dogs and cats. Additionally, for each host species the number of individuals and the mean faecal excretion per day was determined. Results showed that both prevalence and intensity of infection varied significantly between species and between the two villages and neither of the variables gave an adequate picture of the potential transmission. Total daily egg excretion was significantly higher in Chenqiao village compared with Guanghui village. Whereas humans were the main contributors to transmission of schistosomiasis in Guanghui village (80.4%), water buffaloes accounted for nearly 90% and goats for more than 5% of the transmission in Chenqiao village. Hence, the present study suggests that schistosomiasis transmission might vary significantly within Chinese farm districts and successful control should rely on prior transmission index determinations on major potential contributors rather than routine data of prevalence and intensity of infection. Further studies should determine the value of adding other transmission variables like egg hatchability and faecal deposition habits.

Prenatal Schistosoma japonicum infection in piglets: effect of repeated exposure of the dams on treatment efficacy and susceptibility to challenge infections.

This study elucidated the fate of prenatal infections in piglets born by dams repeatedly infected before and during pregnancy with Schistosoma japonicum. Independent variables included repeated infections of the dams and treatment or challenge infection (or both) of the prenatally exposed piglets. Dependant variables were worm counts, fecal and tissue egg counts, weight gain, and gross pathological observations. Fifteen female piglets (the dams) were included, of which 6 received repeated infections with S. japonicum during 6 mo. All dams were inseminated and 10 wk pregnant; 12 of the dams were infected with S. japonicum, of which 6 had been repeatedly infected. Three dams remained uninfected. Eight weeks after delivery, the prenatally exposed piglets (the offspring) were grouped, and 6 of the 12 groups were treated with praziquantel. Four weeks after treatment, 5 groups of piglets were infected with S. japonicum. Groups of piglets were killed either 12 or 22 wk after delivery. Repeated infections of the dam did not prevent establishment of a congenital infection in the pig fetuses. Piglets born with a congenital infection were not resistant to a S. japonicum challenge infection given 12 wk after birth. Neither did praziquantel effectively cure the piglets nor did treatment of the prenatally infected piglets prevent establishment of a challenge infection given 4 wk after treatment. Results of the present study indicate that prenatal exposure, independently of the dam's infection status, may change the host response to challenge infections and treatment after birth.

Review of North-South and South-South cooperation and conditions necessary to sustain research capability in developing countries.

The paper extracted pertinent aspects of 21 years (1981-2001) of scientific cooperation among Zimbabwe's Blair Research Laboratory (BRL), the Biomedical Research and Training Institute (BRTI), and the Danish Bilharziasis Laboratory (DBL). DBL supported the building of research capacity at BRL through PhD-level training and short courses on research training organized by BRTI. The BRL-BRTI-DBL cooperation involved institutional support, scientific training, joint research programmes, and technology transfer, and forms a basis for the discussion of North-South and South-South collaboration in this paper. As the collaboration matured, DBL researchers began cooperating with their counterparts at BRL in internationally funded research programmes and partnerships based on mutual interests and responsibilities. Several research projects were formulated under co-principal investigators from the two institutions and later extended to other European and US institutions. An impressive outturn (18 PhDs) of postgraduate students undertaking field-based PhD work was accomplished from 1990 to 2001. As the socioeconomic situation in Zimbabwe deteriorated from 1999, significant attrition of senior scientists began to affect some of BRL's core functions in support of the Ministry of Health's programmes. In solidarity with BRL, DBL and BRTI jointly implemented a management-strengthening project to reduce deterioration of research productivity by retaining mid-level research managers. BRTI, able to respond rapidly to research needs in the Southern Africa Development Community (SADC), is not in competition with national research institutions and universities. An advisory committee of SADC stakeholders sets its priorities. The framework for South-South cooperation is research training to facilitate national scientists to attract resources from local and international funding agencies. It has established a National Institutes of Health-accredited ethical review board that provides ethical assurance for BRTI and non-BRTI-administered projects. Over the last eight years, BRTI has established regional and international legitimacy, and many funding agencies accept the role of the organization in 'Third Country Training for South-South Cooperation'. The article concludes by identifying essential conditions for sustaining research capability at BRL and similar institutions in developing countries. In rolling out a new ethos for research, great expectation is placed on the success of the New Partnership for Africa Development.