Intestinal protozoa and intestinal helminthic infections in displacement camps in Sierra Leone.

Displacement and refugee camps provide ideal grounds for the transmission of parasites and increase the risk of acute respiratory infections, diarhoea diseases, and intestinal parasitic infection. Cryptosporidium parvum, Giardia lamblia, Entomoeba histolytica, Ascaris lumbricoides, hookworm infection, Schistosoma haematobium, S. mansoni and Strongyloides stercoralis are important cosmopolitan intestinal parasites that are common among children, the immunocompromised and displaced populations. Five hundred and eighty one residents from 5 Internally Displaced Persons (IDPs) Camps voluntarily participated in the study by providing stool and urine samples for analysis. The stool specimens were used for the detection of Cryptosporidium specific and Giardia specific antigens by the DMSO modified Acid-Fast and Trichrome-PLUS stain for C. parvum and G. lamblia and E. histoyltica respectively. Stool specimens for the demonstration of helminth eggs and larvae were prepared by the modified Kato technique. One hundred and seventy eight (31%) of the 581 camp residents that submited samples were children below 10 years of age and were selected because they were screened for various forms of malnutrition. However, the data on C. parvum and G. lamblia were included in the analysis for all parasites. More children were positive for G. lamblia (29%) than for C. parvum (10%) and 5% had double infection with both parasites. The antigen positive rate decreased with age for C. parvum and G. lamblia infections. Adult samples were also examined for the C. parvum, G. lamblia, E. histolytica, A. lumbricoides, hookworms, S. haematobium, S. mansoni and S. stercoralis. The prevalence of hookworm was highest at Parade Ground Camp (50%) and hookworm had the highest pevalence rate of 18% among the 581 IDP residents followed by S. mansoni (16.7%) and A. lumbricoides (15%). The overall prevalence of E. histolytica among the study population was 9.0%. The results of this study indicate that intestinal protozoan and helminth parasites are highly prevalent among camp residents in Sierra Leone with five (5) different helminth parasites demonstrated in the stool specimens of residents in the five IDP camps.

High prevalence of bedbugs Cimex hemipterus and Cimex lectularis in camps for internally displaced persons in Freetown, Sierra Leone: a pilot humanitarian investigation.

The prevalence of bedbugs Cimex hemipera and C. lectularis was investigated in camps for the internally displaced persons (IDPs) in Freetown, Sierra Leone. Two hundred and thirty eight rooms were searched during the day and at night, and 233 (98%) of those rooms in 30 booths were infested with different life cycle stages of bedbugs. There hundred and ninety-eight (68%) of the bedbugs were adults, 145 (24.8%) were nymphs of various instars, and 41 (7%) were clusters of eggs. Significantly (P > 0.05) more bedbugs were recovered during the night inspections 64.6% as compared to 35.4% during the day inspections. In addition, more adult bedbugs were recovered at night than during the day, a manifestation of their peak feeding period. Of the total of 570 adults and nymphs collected and identified, 320 (56.1%) and 250 (43.9%) were Cimex lectularis and Cimex hemipterus respectively. Clinical examination of 221 individuals living in the booths during 3 consecutive weeks of examinations and treatment for conditions suggestive of bedbug infestation (bites and skin reactions as well as treatments for other health and medical conditions) showed that 196 (86%) had wheals as a direct result of bedbug bites. The data of this pilot humanitarian investigation shows a high prevalence of bedbug infestation in these displacement camps. It is recommended that some control measures be instituted, like residual insecticide application along with integrating control methods within the primary health care system, because bedbugs are a source of great irritation and sleepless nights that could lead to stress.

Apparent drug failure following artesunate treatment of Plasmodium falciparum malaria in Freetown, Sierra Leone: four case reports.

Four cases of Plasmodium falciparum malaria who presented in Sierra Leone in November-December 2000 apparently failed to respond to treatment with artesunate. Three (75%) of the cases fulfilled the World Health Organization's criteria for late treatment failure. Although artesunate ranks only sixth as the first-line drug used by clinicians for the treatment of uncomplicated malaria in Sierra Leone, it is widely sold over the counter in pharmacies in the country. The indiscriminate and injudicious use of artesunate among the Sierra Leonean population is likely to increase the level and frequency of resistance among the local strains of P. falciparum. It is recommended that artesunate be reserved for patients who fail to respond to treatment with another of the antimalarial drugs available. Even then, the artesunate should preferably be used in combination with other, longer-acting antimalarial drugs, to slow the development of further resistance.

Sarcoptes scabiei infestation among children in a displacement camp in Sierra Leone.

The prevalence of scabies was investigated among a study population of 125 children between the ages of 1-15 y. Confirmation of scabies was done by clinical examination of each child and by the identification of the mite by microscopically examining the scrapings from the scabies-like lesions. The prevalence was age dependent, with children under five years accounting for 77%, peaking to 86% among the 5 to 9-y-olds, and steadily declining with an increase in age. Lesions were found on almost all parts of the body, but lesions were more commonly located on the fingers, legs, hands, face, stomach, and genitalia. Sarcoptes scabiei var hominis was recovered from 84 (67%) of the 125 skin scrapings examined. The prevalence of scabies is high in children in the displacement camps, suggesting that it may be a serious public health problem not only in these camps, but also in the entire country. This may be due to the fact that certain environmental conditions like civil unrest, overcrowding, poor personal hygiene, poverty, and ignorance, which are conducive to the spread of scabies, is characteristically present among the camp residents. Control programs should be put in place and implemented in an integrated nature, by reducing overcrowding, and by improving health education, personal hygiene, treatment and surveillance among high-risk populations.

The usefulness of defined clinical features in the diagnosis of HIV/AIDS infection in Sierra Leone.

Sierra Leone ranks at the bottom of the global World Bank Development Index based on multiple health and economic indices and lacks the resources to purchase HIV diagnostic kits. Our study has defined some common clinical features presenting HIV infection that could form clinical algorithms for the diagnosis and recognition of HIV infection by health workers in Sierra Leone. In a private clinic in Freetown, Sierra Leone, West Africa, 106 out of a total of 124 patients presenting with various symptoms and strong clinical suspicion of HIV infection within a two-year period (1999 and 2000), were deemed positive by two different ELISA tests. The prevalence of HIV infection seen in this private clinic in Freetown in 2000 was 14.89% as compared to 9.25% in 1999. The positive predictive value of our clinical diagnosis of HIV/AIDS infection was 85.5%. The male:female ratio of the patients in our series was 1:1.9, with a mean age of 39 years for males and 28 years for females. HIV infection was found in a cross-section of the population that we examined. Heterosexual contact appeared to be the major mode of transmission amongst our patients and there seemed to be a significant epidemiological risk of HIV infection amongst those who traveled to other countries in the West African sub region. Common clinical features in decreasing frequency were fever (92.5%), weight loss (84.1%), lymphadenopathy (78.3%), cough (48.1%), diarrhea (37.7%), candidiasis (32.1%) and body aches (30.1%).

It all began with Ronald Ross: 100 years of malaria research and control in Sierra Leone (1899-1999).

It was in Sierra Leone, 100 years ago in 1899, that human malarial parasites were first observed in wild-caught Anopheles gambiae and An. funestus, the principal vectors of malaria in Africa. In the same year, Ronald Ross initiated the first antilarval measures for malaria control. This paper reviews 100 years of malaria field research and control in Sierra Leone, which became known as the 'White Man's Grave' in the 19th century largely because of the high malaria-related mortality amongst Europeans living there. The establishment of a field laboratory for the Liverpool School of Tropical Medicine in Freetown in 1920 made Sierra Leone the centre for malaria field research in Africa up to and during the Second World War. Eminent malariologists including Ronald Ross, Samuel Christophers, George Macdonald, Leonard Bruce-Chwatt, Brian Maegraith, Ian Macgregor, Brian Greenwood and Michael Service visited Sierra Leone for malaria-related activities. This review highlights the tremendous efforts made towards defining the epidemiological picture of the disease and the most effective means of combatting it. Malaria control in Sierra Leone, as in many other parts of the world, used to be based largely on mosquito eradication. However, experience gained over the past 100 years has shown that mosquito control is often not cost-effective in areas where the interruption of transmission cannot be sustained. Emphasis should now be on early diagnosis, treatment with effective antimalarials, and the selective use of preventive measures including vector control and insecticide-treated materials where they can be sustained.

Analysis of west African hunters for foamy virus infections.

Foamy viruses are a genus of complex retroviruses that infect a wide variety of mammals. However, a clear association with any disease process has yet to be proven for these viruses. A higher human seroprevalence was reported in African populations, perhaps due to exposure to simian foamy viruses (SFV) endemic in primates. However, the earlier serologic surveys were not confirmed by studies employing nucleic acid amplification. Foamy virus infections of humans clearly do occur as rare zoonoses among primate center or laboratory workers exposed to captive primates or their blood. We sought to detect foamy virus infections in a cohort of humans also presumed to be exposed to SFV, i.e., West African hunters. We constructed recombinant vaccinia viruses that expressed human foamy virus (HFV) Gag or Env polyproteins in mammalian cells. The sera from 17 monkey hunters or several controls were tested in radioimmunoprecipitation assays (RIPAs) against the recombinant HFV proteins. Chimpanzee sera or HFV-positive human sera immunoprecipitated gp130, the HFV Env precursor, as well as p74, the HFV Gag polyprotein. None of the hunters' sera recognized both of these recombinant proteins. We then employed a nested polymerase chain reaction (PCR) analysis of the hunters' DNA but also failed to detect foamy virus infections. Therefore, by utilizing a recombinant RIPA and a nested PCR assay, we have not identified foamy virus infections occurring naturally in hunters exposed to wild monkeys in West Africa.

Parasitological and clinical studies on Wuchereria bamcrofti infectionin Moyamba District, Sierra Leone.

A total of 302 people were examined in 3 villages in the Moyamba District, Sierra Leone of microfilaria (mf) and clinical signs of Wuchereria bancrofti infection. Mf rates were 34.5% and 31.8% for Bonganema, Old Mosongo and Pelewahun respectively. The average mf rate of those examined was 34.8%. Analysed by age and sex, the highest mf rates were observed in males of age >/=21 years (46 - 56%). The relative risk of infection was significantly lower (P<0.000) for 5-10 year olds than 11+ year old individuals. Clinical studies of 284 individuals of age >/=11 years showed that recurrent fever was the commonest clinical sign observed and the rate was 5.9%. For the ages >/=41 years, the recurrent fever was 10%. The average hydrocele and elephantiasis rates were 2.5% and 1.1% respectively. For the ages >/=41 years, the hydrocele and elephantiasis rates were 4% and 3% respectively, indicating that Filariasis is an important public health problem in the area. Annual mass treatment of the study area residents with ivermectin for onchocerciasis has begun. Ivermectin has been reported to be effective for control of lymphatic Filariasis. The displacement of the population due to the undeclared war in the area will certainly negate the effects of the mass treatment programme.

Filariasis in the Kaiyamba Chiefdom, Moyamba District Sierra Leone: an epidemiological and clinical study.

In a cross-sectional epidemiological and clinical study of human filariasis, 630 individuals were examined for Onchocerca volvulus, Wuchereria bancrofti and Mansonella perstans infections in five communities in the Kaiyamba Chiefdom, Moyamba District, Sierra Leone. The overall prevalence of O. volvulus infection in males 144(39.1%) and females 94(35.9%) was not significantly different and the sex prevalence rate between communities was also not significant (G = 3, d.f. = 4, P > 0.05). Prevalence of O. volvulus was significantly lower (G = 42.331, d.f. = 5, P < 0.001) in the 5-9 age group (13.3%) compared to the 40-49 age group (61.9%). Sixty-four (10.2%) and 38(6.0%) of individuals examined were positive for W. bancrofti and M. perstans infections respectively and prevalence of both infections in the five communities was not significant. Mixed infections with the all three filaria parasites were recorded in 10(3.2%) of the individuals. One hundred and sixty-four (71.3%) clinical cases due to W. bancrofti were inflammatory in nature; 36.5% were chronic, of which, 26.6% were hydroceles and 9.4% involved elephantiasis of both the scrotum and the lower legs. All 19(3.0%) of M. perstans-related clinical cases were inflammatory. Ninety-three(63.3%) of O. volvulus positive individuals that presented symptoms were inflammatory in nature, 14(9.5%) had ocular symptoms and 57(38.8%) had subcutaneous nodules. These data indicate that infections due to O. volvulus, W. bancrofti and M. perstans may be of public health importance in Sierra Leone.

Integrated control of Onchocerca volvulus infection in a hyperendemic zone in Sierra Leone.

A simplified integrated method of onchocerciasis control involving mass chemotherapy with ivermectin, nodulectomy and health education was carried out in south central Sierra Leone. The prevalence of Onchocerca volvulus in the village community ranged from a low of 7.4% among the International School children to a high of 97.0% in Gbessebu. There was a significant (3-4%) overall reduction in the rate of infection after one year of ivermectin treatment (G = 2565.97, df = 11, P < 0.001). In addition, ivermectin treatment had a significant effect on the college community (G = 1168.21, df = 5, P < 0.001) and from year to year (G = 187.29, df = 1, P < 0.001), though the effect indicates the reduction varied between communities. Mass ivermectin treatment significantly (G = 1 3.79, df = 1, P < 0.005) reduced the rate of infection among school children, while the prevalence and intensity of infection was reduced by nodulectomy. Health education involving the community gave us an entry point and allowed us to gain the maximum cooperation and participation from the communities.

Saulea vitrea and low prevalence of schistosomiasis.

Thirty-six sties, including pools, small streams, large rivers, and rice fields swamps were examined for the intermediate snail hosts of schistosomiasis and other mollusca in 19 villages spanning 4 chiefdoms in Sierra Leone. Half of the Saulea vitrea collected were examined for possible infection and none was found to be infected. In addition, we examined 785 stool and 913 urine samples from children living in the villages and found low prevalence and intensity of S. haemotobium (1.8%; 1.9XG) and S. mansoni (1.9%; 2.1XG) respectively. The low prevalence and intensity of infection with schistosomiasis where S. vitrea is in abundance suggest some effect of S. vitrea on schistosome snail intermediate host, but the mechanism remains unknown.

Immunoglobulin G subclass responses of children during infection with Onchocerca volvulus.

To characterize the patterns of immunoglobulin G (IgG) subclass and IgE reactivity during the early stages of onchocerciasis, sera were collected from 224 children (age groups, 2 to 5, 6 to 10, and 11 to 15 years) residing in a region of Sierra Leone where Onchocerca volvulus is endemic, and these samples were tested by enzyme-linked immunosorbent assay for their reactivity to adult antigens (OvAg) and against four recombinant proteins (OV11, OV27, OV29, and OV16). Over 88% of the samples contained detectable levels of anti-OvAg IgG. In samples from microfilaria (MF)-positive children, IgG4 responses were significantly elevated and constituted on average 39, 35 and 28% of the total IgG responses for the age groups of 2 to 5, 6 to 10, and 11 to 15 years, respectively. For MF-negative individuals, the mean contributions of IgG4 to the total IgG response were 11% (2 to 5 years), 27% (6 to 10 years), and 56% (11 to 15 years). OvAg-specific IgE was detectable in the sera from both MF-negative and MF-positive individuals. To increase the specificity of the response, recombinant antigens OV11, OV27, and OV29 were tested individually or as a cocktail. Nearly 50% of the MF-negative children and 85% of the MF-positive children had detectable levels of IgG against at least one of the recombinant antigens. Only a small portion of the IgG against the recombinant peptides was IgG4. The prevalence of IgG against OV16 in samples from MF-negative children was 51%, and that for MF-positive children was 75%. The general profile of the humoral immune responses mounted by both MF-positive and a large percentage of the MF-negative children during the initial phases of infection with O. volvulus is similar to the profile reported for adults harboring chronic O. volvulus infections. These results suggest that very quickly after infection, the interactions between parasite and host result in an immunological environment that may contribute to the maintenance of a long-term, chronic infection.

Intestinal parasitic infections among rural farming communities in eastern Sierra Leone.

A study carried out in four rural, mainly farming villages in the Gorama Chiefdom, Kono District, Eastern Sierra Leone revealed that intestinal helminth infections are prevalent in this area of Sierra Leone. Out of the 1164 persons of all ages who were examined, 853 (73.5%) proved positive for at least one intestinal helminth infection. Ascaris lumbricoides was the most common helminth encountered (37.5%), followed by hookworms, 12.9%; Trichuris trichiura, 12.6%; Schistosoma mansoni, 5.6%; Strongyloides stercoralis, 3.8%; tapeworms 1.0%, and multiple infections were common. Adults used poorly built pit latrines, while children defecated indiscriminately and unsupervised around houses and in the nearby bush. In addition, in most of the villages, domestic water was obtained from polluted streams and rivers. Only one village had protected pipe borne water supply. The high prevalence of intestinal helminth infections in this area results from constant infection and reinfection caused by poor sewage disposal, poor environmental health, and the low socioeconomic status prevailing in these communities.

Intestinal helminth infections in rural school children in Njala, Sierra Leone.

In a survey of five primary schools and one secondary school in and around the Njala University College environment, in Southern Sierra Leone, 1820 school children were examined. Ascaris lumbricoides was the most common helminth encountered (33.3%) followed by Trichuris trichiura (14.6%) and hookworm infection (10.4%). There was striking differences in the rate of infection between the various schools with the International School being the least affected by all parasites. Multiple infections were quite common, with 53.1% having one type of helminth infection, 40% had two types of helminth infections, while 6.9% had three or more helminth infections. School screening should be an important component of Primary Health Care in Sierra Leone since it offers good opportunity for disease surveillance, health education and early detection and treatment of infections before they become chronic.

Evaluation of Onchocerca volvulus-specific IgG4 subclass serology as an index of onchocerciasis transmission potential of three Gabonese villages.

The major objective of this study was to evaluate the usefulness of IgG4 ELISA and Western blot analysis, using a crude extract of Onchocerca volvulus adult worms as antigens, for diagnosing onchocerciasis in a Gabonese paediatric population with mixed filarial infections. The subjects had loaisis, streptocercosis or mansonellosis in addition to onchocerciasis. Control sera from loaisis or mansonellosis subjects residing outside the endemic zone were used to provide the cut-off point for positive results. The IgG4 ELISA had a specificity of 96% but a lower sensitivity of 78.7%. It detected 25 onchocerciasis cases out of 65 individuals who were negative on parasitological examination. Furthermore, the ELISA provided a more accurate picture of onchocerciasis transmission in a village with very low skin microfilarial load. A 27.5-kD antigen was identified on Western blots as a marker of onchocerciasis. The paediatric population provided a reliable window for assessing the parasitologic and serologic parameters in the three villages with disparate levels of onchocerciasis transmission.

Inland valley swamp rice development: malaria, schistosomiasis, onchocerciasis in south central Sierra Leone.

The prevalence of malaria, schistosomiasis and onchocerciasis was determined in 1,106 residents of five villages in the Moyamba District, Southern Sierra Leone, to determine whether inland valley swamp (IVS) development was associated with changes in the prevalence of malaria, schistosomiasis and onchocerciasis in these villages. These parasitic diseases were studied in four villages receiving IVS, Food and Agricultural Organization (FAO) assistance and in one village not receiving FAO assistance. Malaria was the most prevalent infection, detected in 42.6% of the persons examined, followed by O. volvulus (17.7%), S. haematobium (0.6%) and S. mansoni (0.3%). Plasmodium falciparum accounted for 90.4% of the malaria infections, followed by P. malaria (2.1%), P. ovale (0.5%), and mixed infections (7.0%). The trend of infection to O. volvulus increased significantly with an increase in age. S. haematobium (0.6%) and S. mansoni (0.3%) infections were low and no Biomphalaria pfeifferi and Bulinus globosus were found in 33 IVS development swamps examined. These data indicate that IVS development is associated with an increase in the prevalence of malaria infection, but not in the prevalence of O. volvulus, S. haematobium and S. mansoni.

The head louse in Sierra Leone: an epidemiological study among school children, in the Njala area.

A survey of five primary schools in the Njala area, Sierra Leone showed that Pediculus humanus capitis infestation is wide-spread. The overall prevalence was 6.8% among 1007 school children examined. Infestation rates varied between schools from 1.4% to 14.6% and the prevalence of infestation increased with age, from 3.1% among class I children to 10.2% among class IV and decreased to 4.9% among class VI children. Females had a higher infestation rate (8.3%) than their male counterparts (5.4%). The infestation rate was higher' in children whose fathers were Farmers (9.4%) followed by Traders (7.8%), Artisans (6.5%) and Professionals who had the lowest infestation rate of (5.8%). Sharing of beds, beddings and combs had a significant effect (P < 0.01) on the rate of infestation. The infestation was light, therefore, impetigo was minimal. Overcrowding at home is the main factor facilitating the transmission of the infestation from one head to another among these children.

Anti-Onchocerca volvulus immunoglobulin subclass response in children from Sierra Leone.

The humoral immune responses of a paediatric population of 224 children, 2-15 years of age, residing in an onchocerciasis endemic area of Sierra Leone, were studied to gain information that may be useful in the serodiagnosis of prepatent and low-level infections with Onchocerca volvulus. The antigen-specific levels of IgG and IgG4 were determined and evaluated in the context of the parasitological status of the child. Over 87% of the microfilaria-negative children had significant levels of antigen-specific antibodies against O. volvulus, suggesting that a large percentage of this paediatric population were harbouring prepatent or low-level infections. Over 60% of the children in the group that had detectable numbers of microfilariae in skin snips had elevated levels of O. volvulus-specific IgG4. In contrast, only 23% of the microfilaria-negative children had detectable IgG4 responses. The results presented here indicate that measures of O. volvulus-specific IgG4 may be a useful indicator of the parasitological status of children during the very early stages of onchocerciasis.