School-based schistosomiasis control programmes: a comparative study on the prevalence and intensity of urinary schistosomiasis among Nigerian school-age children in and out of school.

A cross-sectional study was conducted in February 1998 on the prevalence and intensity of urinary schistosomiasis among school-age children in and out of school at Adim village in Nigeria to test the objective of delivering a control programme through the school system. School enrollment figures and non-attendance rate were collated from questionnaires that were self-administered by heads of families. Prevalence and intensity of infection were determined following filtration of urine and counting of carbol fuchsin-stained eggs of Schistosoma haematobium. The rates of regular school attendance, irregular attendance and non-attendance were 69.1%, 5.1%, and 25.8%, respectively. These indices were not significantly associated with the age of the schoolchildren (P > 0.05). Boys (76.6%) were more associated with regular attendance than girls (61.4%) (P < 0.0001) while girls had a higher rate of non-attendance (32.7%) than males (19.1%) (P < 0.0001). Although more out-of-school children were infected (90.7%) than those in school (86.8%), the difference was not statistically significant (P > 0.05). The same association was established in the variation of mean egg count between the 2 study populations though intensity was higher among out-of-school children. The principal reasons proffered for the high rate of non-attendance listed in their order of importance were: economic, sickness, poor performance, refusal, farming and fishing. A dual method of control that would in incorporate the integration of recognized local authorities is suggested in areas with moderate school attendance rate like Adim, as lack of treatment of infected out-of-school children ensures continuous contamination and re-infection.

The parasitic diseases of school children in Lagos State, Nigeria.

A survey of 5,595 primary school children in Lagos State showed that most of the children were over-loaded with parasitic infestations which included malaria (37.7%), schistosomiasis (13.4%). ascariasis (74.2%), trichuriasis (75.8%), hookworm (29.5%) and tungiasis (49.5%). Multiple infections were observed with about 16.2% harbouring all the causative organisms of the parasitic diseases enumerated above. The high prevalence of parasitic infestations among these children is an index of the community's low level of health and also of inadequate health education, because most of these diseases are preventable if the people are told what to do.

ABO blood groups in malaria and schistosomiasis haematobium.

We sought to determine if there was any relationship between ABO blood groups and susceptibility to malaria and urinary schistosomiasis. In Epe and outlying villages in south-western Nigeria, we examined 681 people for their blood groups, malaria parasitemia and for the presence of Schistosoma haematobium eggs in their urine specimens. Two hundred and sixty-nine individuals were parasitemic for falciparum malaria, 97 subjects had urinary schistosomiasis and 56 people carried concurrent infections of both parasites. Frequencies of the blood groups were 56.68% for group 0, 22.32% for group B, 18.5% for group A and 2.50% for the AB group. The rates of infection with malaria and/or schistosomiasis showed no significant association with the frequencies of the ABO blood groups.

Malaria and its treatment in rural villages of Aboh Mbaise, Imo State, Nigeria.

We examined the malaria situation among 489 children under 5 years of age in the rural villages of Aboh Mbaise, Nigeria, using a combination of a standard questionnaire technique and laboratory diagnosis to confirm clinical observations. The results show a high prevalence rate of 52.8% for Plasmodium falciparum in this area. The geometric mean parasite density (GMPD) was 19,361.4/mm3. The proportion of children with fever and/or parasitaemia was not related to age, although the numbers in the febrile group appeared to increase with age. Using 37.5 degrees C as the threshold for fever, 48.7% of the heavily infected group (more than 1000/mm3) were afebrile while 51.3% were febrile. High grade temperatures above 38 degrees C were associated with high parasitaemia above 10,000 parasites/mm3. Of the 911 children who died in the area within the last five years, 22.4% died of fever of unknown origin, 39.7% from malaria, 22.5% from convulsion, 10.5% from diarrhoea and 4.6% from cough. Chloroquine is the drug of choice for the treatment of malaria and there were many cases of drug abuse, and use of sub-curative doses prescribed by non-medically qualified staff.

ABO blood groups distribution in relation to hepatitis B surface antigen and the presence of lipoidophil antibodies.

Three hundred and thirty donors were screened for HBs Ag using direct passive haemagglutination and the presence of Lipoidophil antibodies as detected by VDRL test. Blood group O donors had the highest HBs Ag prevalence rate of 4.3% as against the 0% frequency for group AB donors. There were no significant association between ABO blood group distribution and the presence of HBs Ag (P greater than 0.05). 11 donors in all were positive for HBs Ag giving a total prevalence of 3.3%. The sera of 27 blood donors (8.2%) contained lipoidophil antibodies. The highest percentage of VDRL test positivity was in blood group B donors (22.7%) followed by group O (9.1%). None of the 6 group AB donors had a reactive sera. Test of significance showed that there was no association between ABO distribution and the presence of lipoidophil antibodies. In conclusion, it is stated that since none of the blood donors that was reactive to the VDRL reagin carried HBs Ag, hepatitis virus B unlike other viral infection, may not elicit the production of lipoidophil antibodies.

The status and consequences of Mansonella perstans infection in Calabar, Nigeria.

Two aetiological studies on filariasis were conducted from January to June, 1993. In the first study, 690 blood samples clinically diagnosed of filariasis were examined. In the other, 150 blood samples and 150 skin snips collected from the same group of eye clinic Patients clinically diagnosed of filariasis were investigated. Of the 690 subjects, 108 (15.64%) had filariasis with M. perstans and Loa loa accounting for 98.15 and 1.85% of positive cases respectively. Among the eye clinic patients, 16% had M. perstans while O. volvulus was seen in 4% of patients. There was no concurrent infection with these two agents. A statistically significant association existed in the frequency of M. perstans in the different ages treated (p > 0.01) while non existed by sex (p > 0.01). The possible involvement of M. perstans in ocular filariasis and its treatment are discussed.

Urinary symptoms and blood pressure of children with Schistosoma haematobium infection in south-eastern Nigeria.

The urinary symptoms and blood pressures of 510 children (aged 5-15 years) with Schistosoma haematobium infection in Ijiman community, Cross River State of Nigeria, were studied in 1992. The prevalence rate of infection was 44%, a majority of the children presenting with light infection. Significant symptoms were visible haematuria, dysuria, suprapubic pain and strangury. The sensitivity and specificity of these symptoms were too low for them to be recommended as distinct clinical diagnostic criteria. The impact of the disease could not be demonstrated on blood pressures of the children. Nevertheless, urgent control measures with emphasis on the provision of ventilated improved pit toilets and potable water are strongly recommended for the control of the disease as persistent infection is known to mask manifestation of severe complications till an older age.

Problems of chloroquine-resistant P. falciparum in Nigeria: one antimalaria drugs' utilisation in metropolitan Calabar.

We studied the antimalarial drugs utilisation pattern in urban Calabar, with a view to determining what drugs people take when they have malaria attack and who diagnoses and prescribes the drugs. We used a standard questionnaire data sheet to record the results of the interview carried out by the authors. Malaria symptoms and the drugs consumed were diagnosed and prescribed respectively by self (54pc), qualified medical doctor (32pc) and others including paramedical staff (2pc). The rest (12pc) took traditional remedies. The antimalarial drugs (chloroquine, fansidar, camouqin) were chosen because of their efficacy/popularity (21pc), cheapness (43pc) and availability (34pc). Among those interviewed, only 21.2pc took the adequate curative dose of 25 mg/kg chloroquine for 3 days according to WHO recommendations. Majority of the consumers took their drugs orally, but some (17pc) had chloroquine injections, administered, in some cases, by ill-qualified patient medicine dealer. The results show that there is an association between the level of education and the pattern of remedy sought by the respondents (p less than 0.05). Self-medication was practised significantly more by those with formal education than by those without (p less than 0.05). The trend of consulting patent medicine dealers for prescription decreased with acquisition of more formal education. Conversely, significantly more of the respondents with higher education consulted qualified medical doctors or paramedical staff (P less than 0.05). Two aspects of drug abuse observed here, i.e. the utilisation of sub-curative doses of chloroquine and monotherapy are believed to be two of the factors that lead to the several chloroquine treatment failures which have been recently reported in Calabar, and other areas of Nigeria.

New trends in chloroquine efficacy in the treatment of malaria: significance of low (scanty) parasitaemia in an endemic area, with emerging chloroquine-resistant P. falciparum.

In a continuous malaria therapy surveillance, using in vivo (WHO) seven-day-test, extended to 14 days follow up, we evaluated the significance of low (scanty) parasitaemia, in an area with chloroquine resistance P. falciparum (CRPF), where self-medication is widely practised. We found that 30.9 pc of the patients screened had Plasmodium species, and 71.4 pc of these had low parasite counts of less than 500 parasites/mm3, whole blood. Eight pc of these were febrile and 41.7 pc of the parasite strains were not susceptible to chloroquine. Parasite strains from four of the patients were also resistant to other antimalarials. These patients gave psychosomatic symptoms, and were seen by a psychiatrist. We conclude that 41 pc of the patients with low parasite counts consist of patients with CRPF and/or multiple-drug resistant P. falciparum in this area. These do not only cause chronic anaemia, but also may be responsible for moderate psychosomatic symptoms in all ages.

Effect of Schistosoma haematobium infection on the physical growth and school performance of Nigerian children.

A cross-sectional study of urinary schistosomiasis among 510 primary school children in Ijiman community in south eastern Nigeria was undertaken in May 1992. Schistosoma prevalence and intensity of infection including the impact of the disease on the physical growth and school performance of the subjects aged 5-15 years was assessed. Prevalence of Schistosoma haematobium was 44 pc with the rate rising progressively with age, with a peak prevalence at 10-15. The ova burden was of light intensity (1-49 ova/10 ml) in a majority (73 pc) of the cases. No significant impact of the disease could be demonstrated regarding anthropometric parameters, school attendance and academic performance among the infected children compared with the controls. The lack of discernable effect of S. haematobium infection on these parameters is similar to the general pattern in the west African sub region and is attributed to the generally light ova burden among these children. It is also suggested that differences in the strains of the parasite between regions may be important determinants of morbidity.

New trends in chloroquine efficacy in the treatment of malaria: chloroquine-resistant Plasmodium falciparum in Anambra and Benue States of Nigeria.

Increasing malaria treatment failures with chloroquine (C25) and reports of chloroquine resistant Plasmodium falciparum (CRPF) led to the field survey of two sites (Agbani and Jato-Aka) both in Primary Health Zone A, using WHO--in vivo seven-day test, modified to 14-day follow-up period. Of the 922 children studied, high transmission rates of 40 pc and 59.2 pc were found in Agbani and Jato-Aka respectively. Varying degrees of parasitologic failures (CRPF), 52 pc in Agbani and 60 pc in Jato-Aka were confirmed. However, chemotherapy with C25 significantly reduced the clinical symptoms of malaria infection, even in the CRPF-cases. The clinical success in the two study sites were 69 pc ad 94 pc respectively.

Congenital malaria in Calabar, Nigeria: the molecular perspective.

Polymerase chain reaction (PCR) has been shown to be more sensitive in detecting low-level parasitemia than conventional blood film microscopy. We estimated the prevalence of congenital malaria using nested PCR amplification of the small subunit 18S RNA gene to detect low-level parasitemia and identify Plasmodium species in 204 mother-neonate pairs. Cord-blood parasitemia was detected in four babies by PCR, giving a prevalence of 2.0%. The newborns of primidgravidae were more susceptible to congenital malaria than those of multigravidae (P < 0.0001). There was a strong correlation between placental malaria and congenital malaria (odds ratio = 10.1, 95% confidence interval = 1.3-76.1, P = 0.0487). We conclude that the prevalence of congenital malaria in Calabar detected by PCR is lower than has been reported in this environment through microscopy.

Efficacy of a combination of praziquantel and artesunate in the treatment of urinary schistosomiasis in Nigeria.

The combined effects of praziquantel and artesunate in the treatment of urinary schistosomiasis were assessed among 312 randomly selected schoolchildren aged 4-20 years in Adim community, Nigeria. In the preliminary screening, infection was confirmed in 327 (38.5%) of the 850 subjects screened. Infected subjects who reported for treatment were then divided into six treatment groups of 52 subjects each; 44 subjects in each group completed their treatment regimens and submitted their urine for post-treatment assessment. Praziquantel and artesunate were administered orally at 40 mg/kg and 4 mg/kg body weight, respectively. Adverse effects due to drug reactions were assessed 72 h after medication and all perceived episodes of illness were treated. Morbidity indicators were assessed 56 days after the final dose of the drug regimens. All treatment regimens were well tolerated. The cure rates were 72.7% in the praziquantel plus placebo-treated group and 70.5% in the artesunate plus placebo group, while the artesunate plus praziquantel group had the highest cure rate (88.6%). Haematuria and proteinuria were extensively reduced after treatment with the three drug regimens. This study confirmed that the treatment of urinary schistosomiasis with the combination of praziquantel and artesunate is safe and more effective than treatment with either drug alone.

Enterobiasis and its relationship with anal itching and enuresis among school-age children in Calabar, Nigeria.

The prevalence of enterobiasis and its relationship with anal itching and enuresis were investigated among 799, randomly selected children aged 5-14 years, who lived, either in an area of high population density or one with a much lower population density, in Calabar, Nigeria. The eggs of Enterobius vermicularis were found in anal swabs (collected with transparent adhesive tape) from 60 (7.5%) of the subjects tested, with the prevalence of infection appearing markedly higher in the 403 children from the area with a high population density than in the 396 from the less densely populated area (11.7% v. 3.3%; P < 0.05). Questionnaire-based interviews were used to determine which of the children suffered from anal itching, enuresis or both. Compared with the egg-negative subjects, the 60 children who were egg-positive for Enterobius were found to be much more likely to be suffering from anal itching (78.3% v. 28.3%; P < 0.05) or enuresis (53.3% v. 36.4%; P < 0.05). Enterobiasis is therefore not a problem that is restricted to the temperate regions of the world, and may be a cause of enuresis or at least a contributory factor in the development of this complaint.

The stabilising factors of parasitic infections in Nigeria.

The pattern of parasitic infections in Nigeria is discussed taking into consideration the status quo, and factors of change which tend to maintain the present situation rather than improving upon it. These factors include rapid urbanisation and uncontrolled population movement, agricultural developments, socio-economic factors, disease and vector control operations and health care delivery system. This rather deplorable situation calls for increased awareness on the part of everybody such that cognisance is taken of the hazards and remedies of these factors of change in order not to jeopardise our laudable development programmes.

Malaria parasite density and body temperature in children under 10 years of age in Calabar, Nigeria.

1,188 children under 10 years of age who attended the children's Emergency Clinic were examined from January to December 1988. Their axillary temperatures were recorded and thick and thin blood smears made to determine the malaria prevalence rate and the parasite density. The results show a high prevalence rate (44.8%) for malaria and this was stable throughout the year. The number of subjects with parasite densities of 100,000/mm3 and over, increased progressively with increase in body temperature such that 74.9% of the parasitemic subjects had high grade temperatures of 38 degrees C and over, while only 11.8% had moderate temperatures of 37.5-37.9 degrees C. The ratio of parasitemic afebrile to parasitemic febrile patients was in the order of 1:6, suggesting that parasitaemia is usually accompanied by fever. There was a steady rise in temperature with parasite density up to 39.5 degrees C, when further increase in parasite density apparently caused no further rise in temperature, suggesting a self-protective efficient feed back mechanism.

PIP: Fever due to malaria may be continuous , intermittent, remittent, irregular, or absent. This study, therefore, investigates whether a relationship exists between body temperature and parasitemia, which could prove helpful in diagnosing and treating children with febrile illness. 1188 children under age 10 attending the children's Emergency Clinic in Calabar, Nigeria, throughout 1988 were examined. The malaria prevalence rate and parasite density were found from measuring axillary temperatures and analyzing thick and thin blood smears. The malaria prevalence rate was found to be stable at 44.8% over the year. The number of children with parasite density of 100,000/sq. mm and higher increased progressively with body temperature. 74.9% of parasitemic children had high-grade temperatures of 38 degrees Celsius and over, while 11.8% had a moderate temperature of 37.5-37.9 degrees Celsius. These results suggest that parasitemia is usually accompanied by fever. Further, temperature increased steadily with parasite density, up to 39.5 degrees Celsius, beyond which point increases in parasite density failed to produce additional rises in temperature.

Human ecology and parasitic infections. 1. The effect of occupation on the prevalence of parasitic infections in Calabar, Nigeria.

One thousand six hundred people belonging to three different occupational groups were randomly selected. Blood, urine and stool specimens were collected from them and processed for the detection of any parasitic infections. The results show 28.5% infection rate with one or more species of intestinal parasites; 50.7% in the school children, 17.3% among the farmers, and 12% among the soldiers. Results of blood examination showed 5.3%, 8.0% and 2.0% infection rates for P. falciparum in the school pupils, farmers and soldiers respectively, while 31.3% of the three groups were infected with the microfilaria of Dipetalonema perstans, and Loa loa. These were found in 60.7% of the farmers and none at all in the other two groups. Urine examination yielded no positive cases of urinary schistosomiasis and only one case of Trichomonas vaginalis. These results reflect the endemicity of the respective parasites, the degree of their sanitary awareness and their exposure frequencies to the pathogens as a result of their daily activities.

Modification of behaviour and attitude in the control of schistosomiasis. 1. Observations on water-contact patterns and perception of infection.

Observations on the water-contact patterns of 2136 residents of Admin community in Nigeria were conducted at four streams between February 1993 and January 1994. Urine samples collected from those observed were used to estimate the prevalence and intensity of Schistosoma haematobium infection. A questionnaire was also completed for each of the subjects, to test their perception of urinary schistosomiasis and its transmission. Infection was detected in 1076 (50.4%) of the subjects, with peak prevalence among those aged 10-14 years. Intensity of infection was more closely correlated with the number of water contacts (r = 0.97) than with the total duration of the exposure (r = 0.77), emphasising the importance of specific/multiple activities, and of the surface area of the body submerged, in transmission. One stream (Culvet) was identified as the main transmission point, with bathing/swimming and fishing as the main activities predisposing people to infection. The awareness of urinary schistosomiasis and its symptom (blood in urine) were high but specific knowledge about the parasite, its vector and the interaction between the parasite and vector in the parasite's life-cycle were extremely low. Activities that require behaviour and attitude modification have been identified and encouraged as components in the control of schistosome-attributable morbidity (in the absence of pipe-borne water).