Sporadic Cryptosporidium infection in Nigerian children: risk factors with species identification.

A cross-sectional study was conducted to investigate risk factors for sporadic Cryptosporidium infection in a paediatric population in Nigeria. Of 692 children, 134 (19·4%) were infected with Cryptosporidium oocysts. Cryptosporidium spp. were identified in 49 positive samples using PCR-restriction fragment length polymorphism and direct sequencing of the glycoprotein60 (GP60) gene. Generalized linear mixed-effects models were used to identify risk factors for all Cryptosporidium infections, as well as for C. hominis and C. parvum both together and separately. Risk factors identified for all Cryptosporidium infections included malaria infection and a lack of Ascaris infection. For C. hominis infections, stunting and younger age were highlighted as risk factors, while stunting and malaria infection were identified as risk factors for C. parvum infection.

Current status of soil-transmitted helminthiases among pre-school and school-aged children from Ile-Ife, Osun State, Nigeria.

A cross-sectional survey was conducted to determine the prevalence and intensity of soil-transmitted helminths among pre-school and school-aged children attending nursery and primary schools in Ile-Ife. Single stool samples were collected between January and March, 2009 from 352 children randomly selected from a total of 456 children attending both private and government schools. The stool samples were processed using the modified Kato-Katz technique, and then examined for the eggs of soil-transmitted helminths (STHs). One hundred and twenty-one (34.4%) samples were positive for STH eggs. The overall prevalences of Ascaris lumbricoides, Trichuris trichiura and hookworm were 33.2%, 3.7% and 0.9%, respectively. The prevalence of STH infection in government schools (47.8%) was significantly higher than in private schools (16.1%) (P < 0.001). The most common type of mixed infection was the combination of A. lumbricoides and T. trichiura (6.8%). The prevalence and intensity of A. lumbricoides rose with age. The lowest prevalence and intensity (7.7%; 0.240 ± 0.136 eggs per gram (epg)) were recorded in the 2- to 3-year-old age group, while the highest prevalence and intensity (58.7%; 1.820 ± 0.237 epg) were recorded in children aged 10 years and above. A questionnaire survey indicated that 73% of the children attending private school had been treated with anthelminthics less than 2 months prior to the collection of stool specimens, while 43% of the children attending government school received anthelminthic treatment during the same period. The findings indicate that STH infections are endemic among schoolchildren in Ile-Ife and that the burden of parasitic infections is greater in government schools than in private schools.

Soil-transmitted helminth infections in Nigerian children aged 0-25 months.

The objective of this cross-sectional study was to determine the prevalence and intensity of soil-transmitted helminths (STHs) in children aged 0-25 months and to identify the associated risk factors for Ascaris lumbricoides infections. The study was conducted in three villages outside Ile-Ife, Osun state, Nigeria in May/June 2005. Stool samples (369) were processed by formol-ether concentration. Ascaris lumbricoides (12.2%) was the dominant infection. Age, father's occupation and dog ownership were identified as the significant risk factors in the minimal adequate model for A. lumbricoides. The odds of being infected with A. lumbricoides increased as the children got older. Children aged 12-17 months and 18-25 months were 8.8 and 12.4 times, respectively, more likely to harbour Ascaris than those aged 7-11 months. The odds of harbouring Ascaris for children whose families owned a dog were 3.5 times that of children whose families did not own a dog. Children whose fathers were businessmen were 0.4 times less likely to be infected with Ascaris than those whose fathers were farmers. The findings from this study suggest that many of these young children, who are at a critical stage of development, are infected with Ascaris and that the prevalence of infection with this parasite increases with age. This study has highlighted the need to incorporate preschool children into deworming programmes in endemic regions and to investigate innovative ways of delivering cost-effective deworming treatment to this high-risk age group.

Epidemiology and patterns of hypertension in semi-urban communities, south-western Nigeria.

OBJECTIVE: To determine the prevalence and subtypes of hypertension among semi-urban residents in south-western Nigeria. METHODS: All adults aged 18 years or older in 10 semi-urban communities were recruited for the study. The blood pressure (BP) reading taken with a validated electronic BP monitor after at least 10 minutes of rest was used in the analysis. Hypertension was defined as BP ≥ 140/90 mmHg. RESULTS: Seven hundred and fifty subjects with a mean age of 61.7 ± 18.2 years participated in the study. The prevalence of hypertension was 55.5%. Stage 2 hypertension was the most common, present among 225 (54.1%) of the participants with hypertension, and 191 (45.9%) had stage 1 hypertension. Of those with hypertension, systolic-diastolic hypertension (SDH) was present among 198/416 (47.6%), while isolated systolic hypertension (ISH) and isolated diastolic hypertension (IDH) were present among 181/416 (43.6%) and 37/416 (8.9%), respectively. The prevalence of hypertension increased significantly with age. CONCLUSION: The prevalence of hypertension was high in these semi-urban communities. Hence, increased awareness and integrating hypertension care into primary healthcare and other community health services in these areas may prove beneficial in ameliorating its adverse effects.

'Leopard skin' as a rapid diagnostic index for estimating the endemicity of African onchocerciasis.

A study was made in five rural districts of Kwara State, Nigeria to assess the possible use of 'leopard skin' (Ls) as a rapid diagnostic technique for estimating the endemicity of African onchocerciasis. The findings revealed that there is a positive association between the percentage of subjects with skin microfilariae (mf) and the percentage with Ls. The prevalence of Ls less than 1% suggests communities with sporadic infection, 1-6% suggests hypoendemic communities and greater than 6% suggests meso- or hyperendemic communities, using mf rates of less than 10%, 10-39%, 40-69% and 70% or greater as the standard to classify sporadic, hypoendemic, mesoendemic and hyperendemic levels of the infection, respectively. The unique merits of Ls as a potential onchocercal index are presented.

Parasitologic survey of onchocerciasis (river blindness) in Babana District, Kwara State, Nigeria.

This study, made between November 1982 and January 1983 to ascertain the prevalence of onchocerciasis in the Babana District of Borgu Local Government Area, Kwara State, Nigeria, showed that 483 (48.6%) of the 993 subjects skin-snipped in 12 communities were infected. The infection rate was significantly higher (P less than 0.001) for males (57.7%) than for females (37.0%), for subjects above 10 years of age (54.0%) than for those who were younger (10.7%), and for the Fulanis (63.8%) than for the Bokos (48.3%). Although various indications suggest that this district has a history of long-standing onchocerciasis, the knowledge of river blindness and its association with blackflies was poor throughout the district and, except for two teachers, no other subjects had ever received onchocercal chemotherapy. These factors, apparently, account for the frequent occurrence and severity of various clinical manifestations and complications of onchocerciasis identified in the district.

Effect of water supply and sanitation on the prevalence and intensity of Ascaris lumbricoides among pre-school-age children in Ajebandele and Ifewara, Osun State, Nigeria.

The relationship between Ascaris lumbricoides infection and provisions for safe water supply and excreta disposal was investigated in Ajebandele and Ifewara, 2 peri-urban communities near Ile-Ife, Osun State, Nigeria, from September 1998 to December 1999. Although there were more facilities for safe water supply (pipe-borne and shallow wells) and sanitation (flush toilets and pit latrines) in Ajebandele than in Ifewara, they were not evenly distributed and only a few families, mainly in Ajebandele, were well provided for. Our results indicated that the prevalence of A. lumbricoides was significantly higher in Ifewara (21.2%) than in Ajebandele (13.1%), and within villages was much lower in houses with tap water and flush toilets. However, the mean intensity of infection was unexpectedly higher in Ajebandele (166.5 +/- 692.0) than in Ifewara (153.1 +/- 485.8) suggesting that the present level of investment in Ajebandele is probably not sufficient to reduce morbidity. These findings confirm suggestions that there is a threshold level of investment below which interventions on water supply and sanitation may not significantly improve human health. Sustainable ascariasis control in the study communities will require significant improvements to existing water supplies and sanitation facilities and any future interventions should incorporate a programme of health education to ensure that the facilities provided are properly used and hygienically maintained.

The role of health education and sanitation in the control of helminth infections.

Health education and sanitation are two important components of primary health care system introduced by the World Health Organization (WHO) as a basis for the prevention and control of communicable diseases. However, the roles of health education and sanitation in disease control have been controversial, especially in the wake of recent advances in safe and effective oral drugs. This article has reviewed the various health education and sanitation interventions around the world to determine what roles they have played in the past relative to other intervention strategies and the role they have to play in future control efforts. It appears clear-cut from the review, that while chemotherapy has been and will remain the best option for morbidity control, sanitation has an important role to play not only to sustain the benefits of chemotherapy but also to protect the uninfected. Health education that is effective, simple and low-cost remains the only tool for creating the enabling environment for both chemotherapy and sanitation to thrive.

Disinfectants/antiseptics in the management of guinea worm ulcers in the rural areas.

The effectiveness of trichlorophenol (TCP), chlorhexidine gluconate plus cetrimide (Savlon) and Izal in inhibiting the growth of bacterial isolates from guinea worm ulcers was investigated. Using an adaptation of the method of Russell and Furr (Russell, A.D., Furr, J.R., 1977. The antibacterial activity of a new chloroxylenol preparation containing ethylenediamine tetraacetic acid. J. Appl. Bacteriol. 43, 253-260) the minimum inhibitory concentration (MIC) values of the three anti-microbial agents for each of the isolated bacteria was determined. Water drawn from the rural guinea worm endemic sites was autoclaved and used for the various dilutions of the anti-microbial agents. At the manufactures' recommended use-dilutions in cases of wounds/cuts/sores, Savlon showed greater effectiveness than Izal and TCP in this order. Probable organic and inorganic inhibitors in water that is usually employed in diluting anti-microbial agents in the rural areas for the dressing of guinea worm ulcers very likely had greatest effect(s) on TCP and least effect(s) on Savlon.

A cost-effectiveness analysis of anthelminthic intervention for community control of soil-transmitted helminth infection: levamisole and Ascaris lumbricoides.

A study to compare effects of mass, targeted, and selective chemotherapy with levamisole as an intervention for the control of Ascaris lumbricoides was carried out in 3 communities in rural Oyo State, Nigeria. Selective treatment was applied in 1 village by treating the most heavily infected 20% of the inhabitants, targeted treatment in the second village involved children aged 2-15 yr, whereas mass treatment was offered to all inhabitants in the third village, excluding infants under 1 yr and pregnant women. Intensity (eggs per gram,) of A. lumbricoides infection was determined immediately before and 3 mo after the period of intervention as a means of assessing the relative efficacy of the treatment regimes. During the field study, information on resource use was also collected for a retrospective cost analysis of the 3 strategies Resources used included manpower, materials, drugs, and transport. The results of the parasitological evaluation on the effect of treatment on egg intensity were then combined with the cost analysis to provide an overall measure of the cost-effectiveness of mass, targeted, and selective interventions. The results were expressed in terms of the cost per 1,000 egg reduction in intensity and the cost per person treated. The results showed the mass and targeted approach to be considerably more cost effective than the selective approach.

A possible genetic factor influencing protection from infection with Ascaris lumbricoides in Nigerian children.

An epidemiological study of Ascaris lumbricoides infections was carried out in primary school children aged 5-16 yr from Ile-Ife, Nigeria. Intensity of infection was assessed directly by means of counting worms passed during a 48-hr period after chemotherapy. Reinfection patterns of A. lumbricoides were assessed at 2 6-mo intervals and statistical evidence of predisposition to infection status was obtained. An investigation of 3 groups of children who were judged to be predisposed not to be infected, to be lightly infected, and to be heavily infected was undertaken. Assignment to the groups was based upon the mean worm burden plus 1 SD above the mean, measured at 2 6-mo intervals. The distribution of class I human leucocyte antigens among the 3 groups of children was described. None of the children who were predisposed to remain uninfected was found to possess the A30/31 antigens in contrast to those children who remained infected.

Schistosoma haematobium infection among schoolchildren in the Babana district, Kwara State, Nigeria.

A study was carried out in the Babana District of Borgu Local Government Areas in Kwara State, Nigeria, to determine the prevalence and intensity of urinary schistosomiasis among schoolchildren. Of 425 pupils found and examined in nine communities, 193 (45.4%) were infected. Infection rates for boys and girls (44.7% and 47.9%, respectively) were not significantly different (P greater than 0.5). Children between 11 years and 13 years of age had the highest prevalence (59.2%), while those between 5 years and 7 years had the lowest (33.6%). However, the proportion (25.9%) of children excreting at least 1000 eggs/10-ml urine sample during their first decade of life was significantly higher (P less than 0.01) than for pupils who were older. There was a positive relationship between schistosomal infection and the prevalence of haematuria and proteinuria. Thus, the prevalences of haematuria and proteinuria were significantly higher among the infected than among the non-infected pupils (P less than 0.01). All the pupils with heavy haematuria (n = 45) and those with heavy proteinuria (n = 14) had at least 150 eggs/10-ml urine sample and 1000 eggs/10-ml urine sample, respectively.

Epidemiology of intestinal helminth parasites of dogs in Ibadan, Nigeria.

An epidemiological study of gastrointestinal helminths of dogs (Canis familiaris) in two veterinary clinics in Ibadan, Nigeria, was conducted between January 2001 and December 2002. Faecal samples collected from 959 dogs were processed by modified Kato-Katz technique and then examined for helminth eggs. The results of the study showed that 237 (24.7%) of the dogs examined were infected with different types of helminths. The prevalences for the various helminth eggs observed were: Toxocara canis 9.0%, Ancylostoma spp. 17.9%, Toxascaris leonina 0.6%, Trichuris vulpis 0.5%, Uncinaria stenocephala 0.4% and Dipylidium caninum 0.2%. The faecal egg intensities, determined as mean egg count/gram of faeces ( +/- SEM), were: T. canis 462.0 +/- 100.5, Ancylostoma spp. 54.1 +/- 8.6, T. leonina 0.8 +/- 0.4, T. vulpis 0.1 +/- 0.0, U. stenocephala 1.0 +/- 0.7 and D. caninum 0.2 +/- 0.1. Host age was found to be a significant factor with respect to the prevalence and intensity of T. canis and Ancylostoma spp. There was no significant difference in the prevalence of intestinal helminth parasites between male (27.0%) and female (22.5%) dogs (P>0.05). The prevalence of helminth parasites was significantly higher (P < 0.05) in the local breed (African shepherd) (41.2%) than in Alsatian dogs (16.2%) or in other exotic breeds (21.0%). Single parasite infections (85.7%) were more common than mixed infections (3.5%).

Morphology of the reproductive system of female Moniliformis dubius (Acanthocephala).

By means of light and electron microscopical techniques, the organization of the reproductive tract of female Moniliformis dubius is described. The tract consists of an efferent duct system associated with 2 ligament sacs present in the body cavity. The efferent duct system consists of uterine bell, uterus and vagina. The uterine bell contains a complex system of routes and is associated with the ligament sacs in a way that facilitates egg sorting. The dorsal and ventral ligament sacs exist with separate cavities at the posterior end, where they are attached to the efferent duct, but merge into a single sac at the anterior of the trunk.

Water level regulation and control of schistosomiasis transmission: a case study in Oyan Reservoir, Ogun State, Nigeria.

The effect of different water discharge patterns from the artificial Oyan Reservoir in Ogun State, Nigeria, on water level fluctuations and on schistosomiasis transmission was investigated between August 1990 and March 1993 to determine the impact of water level regulation on schistosomiasis transmission and control. The results show that transmission was greatly influenced by the pattern of water discharge during the hot dry season (January-April). A high discharge during this period of no rainfall, high temperatures, and intense sunshine stimulated rapid water level fluctuations and lake draw-down, which led to significant reductions in all indices of schistosomiasis transmission, i.e. snail density, snail infection rates, human water contact patterns, and incidence of infection. Although these results support continuous water discharges from the reservoir during the hot dry season, this may run counter to current water management policies. Further investigation is therefore required to harmonize the potential benefits in this type of discharge pattern with the objectives of efficient water management in artificial reservoirs.

Ascariasis in Nigeria.

Nigeria is the most populous country in Africa and projections for the future indicate that the population could reach about 165 million by the year 2000(1). A high proportion of the population is under 15 years of age and the majority of people still live in rural areas(1). These characteristics, in combination with a socioeconomic environment influenced by poverty, poor housing, insufficient sanitation and a need for health education, favour the transmission of the human roundworm Ascaris lumbricoides. In 1986, a WHO report on the prevalence of ascariasis in Africa singled out Nigeria for special comment: 15 million Nigerians are estimated to harbour Ascaris. In this context, and that of their own recent field studies, Celia Holland and Samuel Asaolu review the present state of knowledge of ascariasis in Nigeria.

Efficiency of the salt flotation technique in the recovery of Ascaris lumbricoides eggs from the soil.

The efficacy of the salt flotation technique using saturated solutions of sodium nitrate (specific gravity 1.30) and zinc sulphate (specific gravity 1.16) for separating Ascaris lumbricoides eggs from clay, loamy and sandy soils has been investigated. Ten samples of each of the egg concentrations of 100, 500, 2500, 5000 and 10,000 eggs/25 g of soil were used for each soil type. Using T-test and ANOVA, the number of eggs recovered from sand was significantly higher than from loam and the number from loam significantly higher than from clay. With sodium nitrate, the maximum egg recovery rate was 25.04% from sandy soil at a concentration of 500 eggs/25 g soil while with zinc sulphate it was 13.88% also from sandy soil and concentration of 500 eggs/25 g soil. While the number of eggs recovered increased with soil egg concentration, the percentage of eggs recovered is inversely proportional to egg concentration. The number of eggs recovered with sodium nitrate was significantly higher than with zinc sulphate solution in the three soil types.

Community control of Ascaris lumbricoides in rural Oyo State, Nigeria: mass, targeted and selective treatment with levamisole.

A study to compare effects of mass, targeted and selective chemotherapy with levamisole (Ketrax) as an action for the control of Ascaris lumbricoides was carried out in three communities in rural Oyo State, Nigeria. Selective treatment was applied in one village by treating the most heavily infected 20% of the inhabitants, targeted treatment in the second village involved children aged 2-15 years, while mass treatment was offered to all inhabitants excluding infants under 1 year and pregnant women in the third village. Recommended doses of levamisole were given in the villages, as described above, at 3-monthly intervals during a period of 1 year. Prevalence and intensity (epg) of A. lumbricoides infection were determined immediately before and 3 months after the period of intervention using a modified Kato-Katz technique. In the selective treatment village, no significant differences were found between the pre- and post-treatment egg counts (mean (+/- S.D.) epg 6776 +/- 10,791 versus 4259 +/- 10,909 respectively) of A. lumbricoides in the total population. In the targeted treatment village, significant differences were recorded in pre- and post-treatment egg counts for the total population (9057 +/- 15,797 versus 2579 +/- 6529) among the children alone (10,935 +/- 20,094 versus 992 +/- 3175) and among the untreated adults (7742 +/- 9782 versus 4561 +/- 8798). In the mass treatment village, significant differences in pre- and post-treatment egg count values were also recorded (11,907 +/- 17,220 versus 1489 +/- 5165). The intensity of Trichuris trichiura and hookworm infections among the villagers before and after intervention were not observed to have changed significantly regardless of selective, targeted or mass treatment.

The status of human onchocerciasis in the Kainji reservoir basin areas 20 years after the impoundment of the lake.

A study was made in January 1985 to assess the post-impoundment status of onchocerciasis around the man-made Lake of Kainji, Nigeria, about 20 years after the formation of the lake. The overall prevalence of the infection in the 13 major villages surveyed was 28.5%. The endemicity of onchocerciasis was sporadic (less than 10%) in three of these villages, low (10-39%) in six and medium (40-69%) in four. Although the available pre-impoundment data is inadequate to make a definite conclusion of the impact of the lake formation on the status of onchocerciasis in the area, it is apparent that here, as in most other parts of the country, the prevalence, manifestations, complications and public health significance of onchocerciasis justify the ongoing campaign for the urgent implementation of a nation-wide onchocerciasis control programme in Nigeria.

Observations on the development of the ovarian balls of Moniliformis (Acanthocephala).

Observations have been made on the ultrastructure of objects identified as ovarian balls from female Moniliformis after 1, 3, 5, 7 and 9 days in the rat. Similar objects are present in the body cavity of female cystacanths from cockroaches. The ovarian balls from 1-day-old worms are formed of several cells which are enclosed within a surface coat. During development, the ovarian balls increase in size and cell number and the interval organization appears to become more complex. After 9 days of development in the rat, the surface coat of the ovarian balls can no longer be observed and microvilli are present. It also appears that the supporting syncytium has been formed by this time.