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.

Whipworm and roundworm infections

Trichuriasis and ascariasis are neglected tropical diseases caused by the gastrointestinal dwelling nematodes Trichuris trichiura (a whipworm) and Ascaris lumbricoides (a roundworm), respectively. Both parasites are staggeringly prevalent, particularly in tropical and subtropical areas, and are associated with substantial morbidity. Infection is initiated by ingestion of infective eggs, which hatch in the intestine. Thereafter, T. trichiura larvae moult within intestinal epithelial cells, with adult worms embedded in a partially intracellular niche in the large intestine, whereas A. lumbricoides larvae penetrate the gut mucosa and migrate through the liver and lungs before returning to the lumen of the small intestine, where adult worms dwell. Both species elicit type 2 anti-parasite immunity. Diagnosis is typically based on clinical presentation (gastrointestinal symptoms and inflammation) and the detection of eggs or parasite DNA in the faeces. Prevention and treatment strategies rely on periodic mass drug administration (generally with albendazole or mebendazole) to at-risk populations and improvements in water, sanitation and hygiene. The effectiveness of drug treatment is very high for A. lumbricoides infections, whereas cure rates for T. trichiura infections are low. Novel anthelminthic drugs are needed, together with vaccine development and tools for diagnosis and assessment of parasite control in the field.

The epidemiology of Ascaris lumbricoides and other soil-transmitted helminths in primary school children from Ile-Ife, Nigeria

An epidemiological survey of intestinal helminthiases was conducted on 766 primary school children aged 5-16 years from Ile-Ife, Nigeria. On the basis of stool examinations, the prevalence of Ascaris lumbricoides, Trichuris trichiura, hookworm and Strongyloides stercoralis was 88.5, 84.5, 33.1 and 3% respectively. Intensity of infection was measured indirectly by egg counts for each species of helminth and also by counting worms passed after chemotherapy in the case of A. lumbricoides. The influence of host age and sex on infection levels was assessed. Relationships between the intensities of A. lumbricoides, T. trichiura and hookworm in individual children were identified. After anthelmintic treatment with levamisole, the frequency distribution of A. lumbricoides per host and the relationship between parasite fecundity and worm burden were investigated. Reinfection patterns of A. lumbricoides were assessed at two 6-monthly intervals and even within the narrow age range described, differences were found. In addition, evidence was obtained for predisposition of individuals to heavy or light infection with A. lumbricoides.

Identification of a high diversity of Cryptosporidium species genotypes and subtypes in a pediatric population in Nigeria

A longitudinal study was conducted to determine the epidemiology of Cryptosporidium in 1,636 children in Nigeria. Oocyst prevalence ranged from 15.6% to 19.6% over one year. Cryptosporidium hominis (34), C. parvum (25), C. parvum/C. hominis (4), C. meleagridis (5), Cryptosporidium rabbit genotype (5), Cryptosporidium cervine genotype (3), and C. canis (1) were identified by polymerase chain reaction-restriction fragment length polymorphism analysis. Glycoprotein 60 subgenotyping showed that 28 amplifiable C. hominis isolates consisted of 12 subtypes that belonged to 5 subtype families (Ia, Ib, Id, Ie, and 1 novel subtype family, Ih) and 23 amplifiable C. parvum isolates consisted of 6 subtypes that belonged to 4 subtype families (IIa, IIc, Iii, and IIm). Three C. meleagridis isolates sub-genotyped by sequence analysis of the small subunit ribosomal RNA gene fragment were type 1. This study is the first one to genetically characterize Cryptosporidium species and subtypes in Nigeria and highlights the presence of a high Cryptosporidium diversity in this pediatric population.

Ascaris co-infection does not alter malaria-induced anaemia in a cohort of Nigerian preschool children

BACKGROUND

Co-infection with malaria and intestinal parasites such as Ascaris lumbricoides is common. Malaria parasites induce a pro-inflammatory immune response that contributes to the pathogenic sequelae, such as malarial anaemia, that occur in malaria infection. Ascaris is known to create an anti-inflammatory immune environment which could, in theory, counteract the anti-malarial inflammatory immune response, minimizing the severity of malarial anaemia. This study examined whether Ascaris co-infection can minimize the severity of malarial anaemia.

METHODS

Data from a randomized controlled trial on the effect of antihelminthic treatment in Nigerian preschool-aged (6-59 months) children conducted in 2006-2007 were analysed to examine the effect of malaria and Ascaris co-infection on anaemia severity. Children were enrolled and tested for malaria, helminths and anaemia at baseline, four, and eight months. Six hundred and ninety subjects were analysed in this study. Generalized linear mixed models were used to assess the relationship between infection status and Ascaris and Plasmodium parasite intensity on severity of anaemia, defined as a haemoglobin less than 11 g/dL.

RESULTS

Malaria prevalence ranged from 35-78% over the course of this study. Of the malaria-infected children, 55% were co-infected with Ascaris at baseline, 60% were co-infected four months later and 48% were co-infected eight months later, underlining the persistent prevalence of malaria-nematode co-infections in this population. Over the course of the study the percentage of anaemic subjects in the population ranged between 84% at baseline and 77% at the eight-month time point. The odds of being anaemic were four to five times higher in children infected with malaria compared to those without malaria. Ascaris infection alone did not increase the odds of being anaemic, indicating that malaria was the main cause of anaemia in this population. There was no significant difference in the severity of anaemia between children singly infected with malaria and co-infected with malaria and Ascaris.

CONCLUSION

In this cohort of Nigerian preschool children, malaria infection was the major contributor to anaemia status. Ascaris co-infection neither exacerbated nor ameliorated the severity of malarial anaemia.

Validation of a new test for Schistosoma haematobium based on detection of Dra1 DNA fragments in urine: evaluation through latent class analysis

Background

Diagnosis of urogenital schistosomiasis in chronically infected adults is challenging but important, especially because long term infection of the bladder and urinary tract can have dire consequences. We evaluated three tests for viable infection: detection of parasite specific DNA Dra1 fragments, haematuria and presence of parasite eggs for sensitivity (Se) and specificity (Sp).

Methods

Over 400 urine specimens collected from adult volunteers in an endemic area in Western Nigeria were assessed for haematuria then filtered in the field, the filter papers dried and later examined for eggs and DNA. The results were stratified according to sex and age and subjected to Latent Class analysis.

Conclusions

Presence of Dra1 in males (Se = 100%; Sp = 100%) exceeded haematuria (Se = 87.6%: Sp = 34.7%) and detection of eggs (Se = 70.1%; Sp = 100%). In females presence of Dra1 was Se = 100%: Sp = 100%, exceeding haematuria (Se = 86.7%: Sp = 77.0%) and eggs (Se = 70.1%; Sp = 100%). Dra1 became undetectable 2 weeks after praziquantel treatment. We conclude detection of Dra1 fragment is a definitive test for the presence of Schistosoma haematobium infection.

The definitive test for schistosomiasis has been to detect parasite eggs in excreta. This is effective in children but as people age, it is difficult to find the eggs in spite of suspicion of infection. It also implies that adults have thrown off the infection, and therefore the infection is mainly one of children. However this is not the case as adults with chronic infections can develop severe bladder infection that can progress to bladder cancer. In clinical situations a sensitive test for urogenital schistosomiasis is important. We have recently shown that it is possible to detect schistosome species-specific DNA in urine, even in the absence of eggs in excreta. Here we use latent class analysis to compare sensitivity and specificity of three test procedures, haematuria, eggs in urine and specific DNA in urine in the absence of a gold standard. We show that the latter test is extremely promising for the diagnosis of urogenital schistosomiasis and should also be useful in field studies as it will be able to reveal infections in people frequently presumed to be uninfected. This new test indicated the presence of schistosomes in 10.7% of adults who did not pass eggs in urine specimens.

Patterns of soil-transmitted helminth infection and impact of four-monthly albendazole treatments in preschool children from semi-urban communities in Nigeria: a double-blind placebo-controlled randomised trial

Background

Children aged between one and five years are particularly vulnerable to disease caused by soil-transmitted helminths (STH). Periodic deworming has been shown to improve growth, micronutrient status (iron and vitamin A), and motor and language development in preschool children and justifies the inclusion of this age group in deworming programmes. Our objectives were to describe the prevalence and intensity of STH infection and to investigate the effectiveness of repeated four-monthly albendazole treatments on STH infection in children aged one to four years.

Methods

The study was carried out in four semi-urban villages situated near Ile-Ife, Osun State, Nigeria. The study was a double-blind placebo-controlled randomised trial. Children aged one to four years were randomly assigned to receive either albendazole or placebo every four months for 12 months with a follow-up at 14 months.

Results

The results presented here revealed that 50% of the preschool children in these semi-urban communities were infected by one or more helminths, the most prevalent STH being Ascaris lumbricoides (47.6%). Our study demonstrated that repeated four-monthly anthelminthic treatments with albendazole were successful in reducing prevalence and intensity of A. lumbricoides infections. At the end of the follow-up period, 12% and 43% of the children were infected with A. lumbricoides and mean epg was 117 (S.E. 50) and 1740 (S.E. 291) in the treatment and placebo groups respectively compared to 45% and 45% of the children being infected with Ascaris and mean epg being 1095 (S.E. 237) and 1126 (S.E. 182) in the treatment and placebo group respectively at baseline.

Conclusion

Results from this study show that the moderate prevalence and low intensity of STH infection in these preschool children necessitates systematic treatment of the children in child health programmes.

Trial Registration

Current controlled trials ISRCTN44215995.

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.

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.

Plasma cytokines, chemokines and cellular immune responses in pre-school Nigerian children infected with Plasmodium falciparum

BACKGROUND

Malaria is a major cause of morbidity and mortality worldwide with over one million deaths annually, particularly in children under five years. This study was the first to examine plasma cytokines, chemokines and cellular immune responses in pre-school Nigerian children infected with Plasmodium falciparum from four semi-urban villages near Ile-Ife, Osun State, Nigeria.

METHODS

Blood was obtained from 231 children (aged 39-73 months) who were classified according to mean P. falciparum density per μl of blood (uninfected (n = 89), low density (<1,000, n = 51), medium density (1,000-10,000, n = 65) and high density (>10,000, n = 22)). IL-12p70, IL-10, Nitric oxide, IFN-γ, TNF, IL-17, IL-4 and TGF-β, C-C chemokine RANTES, MMP-8 and TIMP-1 were measured in plasma. Peripheral blood mononuclear cells were obtained and examined markers of innate immune cells (CD14, CD36, CD56, CD54, CD11c AND HLA-DR). T-cell sub-populations (CD4, CD3 and γδTCR) were intracellularly stained for IL-10, IFN-γ and TNF following polyclonal stimulation or stimulated with malaria parasites. Ascaris lumbricoides was endemic in these villages and all data were analysed taking into account the potential impact of bystander helminth infection. All data were analysed using SPSS 15 for windows and in all tests, p <0.05 was deemed significant.

RESULTS

The level of P. falciparum parasitaemia was positively associated with plasma IL-10 and negatively associated with IL-12p70. The percentage of monocytes was significantly decreased in malaria-infected individuals while malaria parasitaemia was positively associated with increasing percentages of CD54+, CD11c+ and CD56+ cell populations. No association was observed in cytokine expression in mitogen-activated T-cell populations between groups and no malaria specific immune responses were detected. Although A. lumbricoides is endemic in these villages, an analysis of the data showed no impact of this helminth infection on P. falciparum parasitaemia or on immune responses associated with P. falciparum infection.

CONCLUSIONS

These findings indicate that Nigerian children infected with P. falciparum exhibit immune responses associated with active malaria infection and these responses were positively associated with increased P. falciparum parasitaemia.

A study of an outbreak of schistosomiasis in two resettlement villages near Abeokuta, Ogun State, Nigeria

Frequent reports of haematuria among resettlers at Ibaro and Abule-titun located close to a newly constructed reservoir, 20 km north-west of Abeokuta, Ogun State, Nigeria, prompted a pre-control survey to assess age and sex distribution of urinary schistosomiasis in the communities. 210 persons were examined at Ibaro and 145 at Abule-titun between April 1988 and February 1989. Overall prevalence was about 80% in both villages, and all age and sex groups examined were affected. The pattern of infection in both villages was similar, prevalence being high in all age and sex groups, and, unlike most endemic communities, the rate of infection was not significantly higher among the 5-14 year age groups. Intensity of infection was also high in all age and sex groups with mean range egg output of between 73 +/- 73 and 2016 +/- 3875 ova/10ml urine at Ibaro and between 231 +/- 122 and 1340 +/- 1786 ova/10ml urine at Abule-titun. This is attributed to an occupation-related high rate of human water contact in both villages.

Seroepidemiological study and associated risk factors of Toxocara canis infection among preschool children in Osun State, Nigeria

Human toxocariasis is caused by the nematode, Toxocara canis and it is a poorly understood phenomenon in Nigeria. Seroepidemiological studies have not been previously carried out among the preschool aged children in Nigeria. A cross-sectional study was conducted in pre-school children in four communities from Osun State, Nigeria between January and July 2016. A total of 308 children Aged 9 months and 5 years were studied comprising 53.2% (164/308) male and 46.8% (144/308) female. Blood samples were collected and screened for the presence of anti-Toxocara IgG antibodies by Western blot analysis based on the excretory-secretory antigens of larva T. canis (TcES), targeting low molecular weight bands of 24 - 35kDa specific for T. canis. Questionnaires were given to parents/guardians of the studied children to collect information regarding relationship between infection and host factors. The overall seroprevalence of Toxocara infection was 37.3%. The seroprevalence in the studied preschool children ranged from 18.2% in children less than one year old to a max of 57.6% in children aged 3 years and above. The logistic regression analysis of risk factors showed that children's age (odds ratio (OR)=6.12, 95% confidence interval (CI)=1.25-29.90, p=0.02), contact with dogs (OR=3.17, 95% CI=1.40-7.20, p=0.01) and parent's religion (OR=0.54, 95% CI=0.32-0.91, p=0.02) were the risk factors associated with Toxocara infection. However, after adjustment by multivariate logistic regression analysis, contact with dogs (p=0.02) remained the only statistically significant risk factor. Preschool children were exposed early in life to T. canis infection as 18.18% of children less than one year old were infected. This is the first serological investigation of T. canis infection among preschool children in Nigeria. The results show high levels of exposure to T. canis infection among the studied group and contact with the dog plays the predominant risk factor. It indicates high transmission with the consequent of visceral or ocular larva migrans and neurologic disorder in these children. The results also provide baseline data for effective prevention strategies of toxocariasis in Southwest Nigeria and the study recommends prompt interventional measures, particularly health education on personal hygiene.

'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.

Targeted anthelminthic treatment of school children: effect of frequency of application on the intensity of Ascaris lumbricoides infection in children from rural Nigerian villages

A study to compare the effects of different frequencies of targeted chemotherapy with levamisole (Ketrax: JAGAL Pharma, Lagos, Zeneca Pharmaceuticals UK) as an action for the control of Ascaris lumbricoides was carried out in 3 communities in rural Oyo State, Nigeria. The targeted group comprised children, age 5 to 15 years, attending primary school within their village. Treatment was provided within the school with the assistance of the school teachers. Three frequencies of targeted treatment were offered. In one village targeted treatment was provided on 1 occasion in 1 year, in another village at two 6-monthly intervals and in the third village every 4 months. Prevalence and intensity (e.p.g.) of A. lumbricoides infection were determined immediately before and after the period of intervention using a modified Kato-Katz technique. In the villages which received treatment once and at 6-monthly intervals, a reduction in post-treatment intensity of A. lumbricoides was observed in the total population but this failed to attain statistical significance. In contrast, within the village which received 4-monthly targeted chemotherapy, a significant reduction in post-treatment intensity of A. lumbricoides was observed in the total population and in the targeted children. In general, reductions in the intensity of A lumbricoides after intervention were not particularly pronounced in untreated children (aged 0-4 years) even in the 4-monthly targeted village, whereas in untreated adults, reductions approached statistical significance in villages which received targeted treatment once and at 4-monthly intervals.

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.

The prevalence and intensity of soil-transmitted helminthiases in rural communities in southern Nigeria

An investigation of the prevalence and intensity of soil-transmitted helminthiases was undertaken in four villages in Oyo state, Nigeria. Diagnosis was based on examination of stool samples for the presence of helminth ova in all age classes. The prevalence of Ascaris lumbriocoides ranged from 61.5-72.2%, of Trichuris trichiura from 65-74%, and of hookworm from 52.4-63% depending on the village concerned. Intensity, assessed indirectly as the mean eggs per gram of faeces (epg), varied with regard to the four villages. The mean egg count of A. lumbricoides varied from 6815-10,823 per gram, of T. trichiura from 127-246, and of hookworm from 122-267. Host age, sex and household size were found to be significant factors influencing faecal egg output, and indirect measure of the intensity of the helminth infections.

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.

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.

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.

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.

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.

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.

High seroprevalence of Toxocara antibodies in pregnant women attending an antenatal clinic at a university hospital in Ile-Ife, Nigeria

BACKGROUND

Human toxocariasis is a neglected zoonotic disease and its impact on human health is underestimated. Studies investigating the occurrence of toxocariasis in pregnancy are very scarce in Nigeria. This study investigated the seroprevalence of Toxocara spp. antibodies as well as the possible risk factors in pregnant women who routinely attended an antenatal clinic in a university hospital in Ile-Ife, Osun state.

METHODS

Blood samples were collected from 413 participating pregnant women between October 2017 and February 2018. Epidemiological data were obtained through a structured questionnaire. The sera were screened for anti-Toxocara IgG antibodies by western blot technique based on Toxocara canis larval excretory-secretory antigens, targeting low molecular weight bands of 24-35 kDa, specifically for T. canis infection.

RESULTS

The overall seroprevalence was 92.49% (382/413). There was no significant difference in the seroprevalence rate of Toxocara spp. infection between pregnant women aged ≤30 y and those aged >30 y (91.63 vs 93.33%; OR 1.28, 95% CI 0.61 to 2.67, p=0.511). The seroprevalence rate increased with the number of miscarriages but there was no statistical significance (p>0.05). Moreover, no significant associations were found between Toxocara spp. seropositivity and other studied risk factors (p>0.05).

CONCLUSION

The high seroprevalence of Toxocara spp. in pregnant Nigerian women needs comprehensive health education regarding personal hygiene and how to avoid exposure to this parasite infection.

Toxoplasma gondii: seroprevalence and associated risk factors among preschool-aged children in Osun State, Nigeria

Background

Toxoplasma gondii is an ubiquitous apicomplexan parasite, which causes toxoplasmosis in animals and humans worldwide. However, little is known about T. gondii infection among preschool-aged children in Nigeria.

Methods

A cross-sectional study of 272 preschool children aged 2.25±1.09 years from four communities (Edunabon, Erin-Ijesha, Ijebu-jesa and Ile-Ife) in Osun State, Nigeria was conducted between January and July 2016, and the demographic data was obtained via questionnaires. Antibody titres against T. gondii of serum samples were assessed by ELISA.

Results

The overall seroprevalence of T. gondii infection was 6.9% (19/272). There was no significant difference in seroprevalence of T. gondii infection between boys (7.04%; 10/142) and girls (6.92%; 9/130; p=0.97). No associations were found between age, gender, parental educational level, occupation and religion, and T. gondii seropositivity. None showed statistical significance between the risk factors tested after multivariate adjustment; nevertheless, residing in Ijebu-jesa community was shown to be associated with an increased risk of infection (p=0.04).

Conclusion

This is the first report of T. gondii infection among preschool children in Nigeria. Prevalence studies such as this could help in the development of strategies for the future for disease prevention and control of T. gondii transmission.