[Tungiasis in Bangou (West Cameroon)]. / Étude de la tungose à Bangou (Cameroun Ouest).

Tungiasis is an ectoparasitosis caused by penetration into the skin of the sand or chigger flea, Tunga penetrans. The epidemiology in Cameroon of this disease, often associated with poverty, is unknown. Accordingly, in August 2008, we conducted a study in Bangou, in Western Cameroon, among a sample of 403 people, divided in 111 families. All data were collected and analyzed with Epi-Info 6.4 software. The prevalence in this population was 32.7%, with infestation more frequent in males (P = 0.013), mostly in children aged 1 to 5 years. The most frequent clinical features were simple inflammatory lesions (100%), infected lesions (2.27%) and necrosis (0.75%). Most patients had a moderate infestation (86.4%), lived in houses with mud floors and brick walls (OR = 2.57; 95%CI [1.67-3.96]), and had animals (dogs) in the household. The principal risk factors were sex- and age-related: boys younger than 15 years old (OR = 5.40; 95%CI [3.20-9.12]) and schoolchildren (OR = 2.57; 95%CI [1.67-3.96]). The main sequelae were toenail deformations (34%).

Community acceptability of the use of low-dose niclosamide (Bayluscide), as a molluscicide in the control of human schistosomiasis in Sahelian Cameroon.

Although field trials of the application of molluscicides for the control of human schistosomiasis have been conducted in several settings, the acceptability of molluscide use at the community level has been poorly documented. The death and putrefaction of aquatic organisms in water treated with niclosamide (Bayluscide), for example, and the yellowish colouration of such water, may decrease the molluscide's acceptability. It may be possible, however, to use doses of a molluscicide that are only just high enough to kill the target snails but not high enough to kill non-target fish and frogs, thereby reducing the application's impact on water quality and colour and improving its acceptability to local communities. In a study in northern Cameroon, Bayluscide WP70 was applied to ponds at concentrations of 0, 0.25, 0.5 or 1 g/m(3). Changes in human contact with the water in the ponds were explored both by direct observation and by in-depth interviews with key informants from the local community. Although all applications of niclosamide greatly decreased human use of the treated ponds for a few days, most informants (99%) were in favour of niclosamide application and only 6% of the interviewees gave change in water colour or bad smell as a reason for not using a particular water body. Over the few days post-application, use of ponds treated with 0.25 or 0.5 g Bayluscide WP70/m(3) was higher than that of the ponds treated with 1 g/m(3), indicating that relatively low-dose applications, if effective in controlling snails, may be more acceptable to local communities than applications at higher doses.

Spatial modelling and the prediction of Loa loa risk: decision making under uncertainty.

Health decision-makers working in Africa often need to act for millions of people over large geographical areas on little and uncertain information. Spatial statistical modelling and Bayesian inference have now been used to quantify the uncertainty in the predictions of a regional, environmental risk map for Loa loa (a map that is currently being used as an essential decision tool by the African Programme for Onchocerciasis Control). The methodology allows the expression of the probability that, given the data, a particular location does or does not exceed a predefined high-risk threshold for which a change in strategy for the delivery of the antihelmintic ivermectin is required.

Loiasis--a neglected and under-estimated affliction: endemicity, morbidity and perceptions in eastern Cameroon.

Loiasis is a neglected disease that may have great social and economic impact in some endemic areas. This study was designed to update the geographical distribution of loiasis and assess the frequency and perceptions of the clinical signs of the disease in the Eastern province of Cameroon. The investigation covered 32 villages and involved 4146 respondents. Human infection with Loa loa was endemic in all the study villages but the prevalence of microfilaraemia generally decreased from south to north. All of the study villages had local names for eye worm and Calabar swellings that varied in meaning and among the various ethnic groups. The most common traditional treatment for eye worm was garlic or onion juice, which is dripped into the affected eye. The body sites that were most affected by Calabar swellings were the upper (30%) or lower (32%) limbs. The swellings were very painful (46%), mildly painful (28%) or painless (26%). Most respondents (94%) reported that the swellings itched. The prevalence of L. loa microfilaraemia in most of the study villages was >20%. These villages are clearly at risk of severe adverse events, with encephalopathy, following mass distribution of ivermectin. The prevalence of the main clinical manifestations of loiasis (i.e. eye worm and/or Calabar swellings) was twice that of detectable microfilaraemia.

Field trials of low dose Bayluscide on snail hosts of schistosome and selected non-target organisms in sahelian Cameroon.

More than 85% of all cases of schistosomiasis in Cameroon occur in the northern sahelian half of the country representing 20% of the population. Several workers have advocated the integrated approach to schistosomiasis control, including snail control, but the death and decay of aquatic organisms, and fish kill that often follows Bayluscide application at the dose of 1 g/m3 decrease its acceptability. The present study was designed to assess the effect of lower Bayluscide doses on snail host and non-target fish, frog, the tadpole kill. Bayluscide was applied to study ponds at concentrations of 0, 0.25, 0.5, and 1 g/m3 (ppm). Pre and post application assessment of snails hosts of schistosomes, fish, frog, and tadpole kill were carried out. All 0.25, 0.5, and 1 g/m3 Bayluscide concentrations reduced snail population significantly. Bayluscide concentration of 0.50 g/m3 applied in two rounds of 0.25 g/m3 resulted in high snail mortality and low lethality to fish, frogs, and tadpoles. Further studies are needed to assess the cost-effectiveness of Bayluscide in the control of schistosomiasis following the simplified approach.

Field trials of low dose Bayluscide on snail hosts of schistosome and selected non-target organisms in sahelian Cameroon

More than 85 percent of all cases of schistosomiasis in Cameroon occur in the northern sahelian half of the country representing 20 percent of the population. Several workers have advocated the integrated approach to schistosomiasis control, including snail control, but the death and decay of aquatic organisms, and fish kill that often follows Bayluscide application at the dose of 1g/m³ decrease its acceptability. The present study was designed to assess the effect of lower Bayluscide doses on snail host and non-target fish, frog, the tadpole kill. Bayluscide was applied to study ponds at concentrations of 0, 0.25, 0.5, and 1 g/m³ (ppm). Pre and post application assessment of snails hosts of schistosomes, fish, frog, and tadpole kill were carried out. All 0.25, 0.5, and 1 g/m³ Bayluscide concentrations reduced snail population significantly. Bayluscide concentration of 0.50 g/m³ applied in two rounds of 0.25 g/m³ resulted in high snail mortality and low lethality to fish, frogs, and tadpoles. Further studies are needed to assess the cost-effectiveness of Bayluscide in the control of schistosomiasis following the simplified approach.

Hematuria and Dysuria in the Self-Diagnosis of Urinary Schistosomiasis among School-Children in Northern Cameroon

The present study was designed to assess the value of self reported hematuria and dysuria in the diagnosis of urinary schistosomiasis at the individual level. A sample of 964 school children of grade 5 and 6 from 15 schools of the French speaking educational system in the Sudano-sahelian zone of northern Cameroon were submitted to a questionnaire related to hematuria and dysuria; and provided a urine sample each. The urine samples were processed using the dip stick and sedimentation methods; and the degree of microhematuria and oviuria determined. In all 964 questionnaires were collected; 843 urine samples examined for microhematuria and 871 for oviuria. The percentage of children reporting hematuria increased with the degree of microhematuria and the intensity of infection. Among the various indicators of urinary schistosome infection; microhematuria had the highest sensitivity (76); followed by self reported hematuria or dysuria (65); and dysuria (52). The specificity was highest for self reported hematuria; and lowest for self reported hematuria or dysuria. The efficiency of self reported hematuria or dysuria increased with the intensity of infection and was highest (100) for heavy infections ( 400 eggs/ml g urine). We advocate the use of self reported hematuria or dysuria for the assessment of S. haematobium at the individual level

High-grade intra-epithelial neoplasia and prostate cancer in Dibombari, Cameroon.

High-grade prostatic intra-epithelial neoplasia (HGPIN) occurs a decade earlier in men of African descent in the US and Brazil, compared to white men. Prostate cancer incidence and mortality is worse in the African-American than in US white men. Sub-Saharan Africa was thought to be a low incidence area. This disparity has been attributed to lifestyle factors such as diet. We report the results of prostatic biopsies, from an ongoing national prostate cancer survey. One hundred and eleven men aged 40 y and over were recruited for medical interview (AUA symptom score), prostate specific antigen (PSA) assay and digital rectal examination (DRE). Between six and 10 cores of random digitally guided needle biopsies were performed on 24 subjects that had either suspicious prostates on digital rectal examination +/ or PSA > or =4 ng/ml. All lesions of the prostate were described on routine histopathology. The Gleason score and proportion of tissue involved with cancer, was determined. Eight men had benign prostatic hyperplasia (BPH), six had cancer, another six had low grade intra-epithelial neoplasia, two had HGPIN, there was one case of BPH and chronic prostatitis and one case of chronic prostatitis only. The cancer patients were aged 58-75 y (mean 66.93 y). Gleason scores ranged from 5 to 9, there was one score of 3. Cancer made up 20-80% tissue samples. HGPIN was found in two cases (mean age 58 y). Significant prostate cancer and the pre-cancerous lesion HGPIN exist in Dibombari, Cameroon. The purported low incidence of prostate cancer may reflect cultural and economic barriers to health care.

The urgent need for environmental sanitation and a safe drinking water supply in Mbandjock, Cameroon.

Studies were conducted to assess the physical, chemical, and bacteriological qualities of drinking water in Mbandjock, Cameroon. Study results indicated that the vast majority of drinking water sources possessed acceptable physical and chemical qualities, according to the World Health Organization standards. However, microbiological analyses revealed that only the waters treated by the Cameroon National Water Company (SNEC) and the Sugar Processing Company (SOSUCAM) were acceptable for human consumption. All spring and well waters presented evidences of fecal contamination from human and/or animal origin. Water from these sources should, therefore, be treated before use for drinking. Since the majority of the population gets its water from wells and springs, there is an urgent need to develop a health education program, within the framework of primary health care, with respect to environmental sanitation and safe drinking water supply in this community.

[Sexuality of adolescent students in Yaounde (Cameroon)]. / La sexualité des adolescents en milieu scolaire à Yaoundé (Cameroun).

Undesired pregnancies are a major cause of school drop out among female adolescents in Cameroun. Studies were undertaken to assess the knowledge and practices of contraceptive methods and the prevention of undesired pregnancies and sexually transmitted diseases (STD). Of the 670 questionnaires that were distributed in 10 class rooms of 5 randomly selected secondary schools of the city of Yaoundé. 574 students responded among whom 233 males and 341 females, aged 12 to 19 years. The responses to the questionnaire revealed that 52% of the students were sexually active, and 56% of these had their first sexual intercourse between 15 and 17 years. The use of contraceptives was reported by 41% of the sexually active students. The main contraceptive methods used were condoms (54%) and periodic abstinence (31%). Periodic abstinence, coitus interruptus report by adolescents is of questionable efficacy in the prevention of STDs, and unwanted pregnancies. The average number of sexual intercourses was 5 times during the month before the survey. The rate of undesired pregnancies was 24%. Knowledge on contraception was more from the mass media (53%), school (21%), peers (16%), than parents (9%). Education for the deculpabilisation of contraception and a better management of sexuality should be undertaken in youth associations and schools. Parents should be taught to dialogue with their children on matters related to sexuality, in order to prevent STDs, unwanted pregnancies, clandestine abortions and their psychological and medical consequences.

Field tests of a village-based mollusciciding programme for the control of snail hosts of human schistosomes in Cameroon.

The feasibility of using unskilled workers at the district or village level to perform mollusciciding activities in arid regions of northern Cameroon was investigated. A simplified procedure for application to temporary ponds, the principal sites of schistosomiasis transmission in that region, was tested. This consisted of mixing the required quantity of niclosamide (Bayluscide, Bayer AG, Leverkusen) with pond water in a plastic watering can and applying the mixture around the circumference. To aid dispersion, the can was repeatedly swept from the perimeter toward the centre of the pond. Two ponds each were treated once near the end of the rainy season at 1 of 3 concentrations: 0.5, 1.0 and 1.5 p.p.m. Following treatment, 100% snail mortality was recorded at all concentrations. A simple, rapid method for determining the quantity of niclosamide needed to treat temporary ponds was also devised. Physical characteristics were determined for 16 potential schistosomiasis transmission sites in the region. An integration of those characteristics was used to develop a simplified scale indicating the quantity of niclosamide needed to treat ponds based on their circumference. The operational feasibility of a village based mollusciciding programme using those simplified procedures was then evaluated in 2 villages. Village health workers demonstrated a high accuracy (87%) in identifying potential schistosomiasis transmission foci and snail host populations were virtually eliminated from treated sites.

[Vectorial fauna at the site of the future dam at Memve'ele(Cameroon)]. / Etude de la faune vectorielle sur le site du futur barrage de Memve'ele (Cameroun).

The present study was designed to assess the health risk of the future hydroelectric dam of Memve'ele with reference to vector-borne diseases. Entomological and malacological surveys were carried out in the project area. The main vectors collected were Anopheles gambiae and An. nili for malaria; Simulium damnosum for onchocerciasis; Glossina palpalis for trypanosomiasis; Chrysops dimidiata and C. silacea for loasis. No snail host of schistosome was reported. The risk of introduction of the diseases they transmit are discussed.

Incidence ecologique du futur barrage de Memv'ele (Cameroun) sur les vecteurs des maladies transmissibles

Les amenagements en eau presentent un atout pour la croissance economique. Cependant ils peuvent etre a l'origine de divers problemes sanitaires si leur gestion n'est pas rationalisee. L'objectif de la presente etude etait d'evaluer l'etat actuel de la distribution des vecteurs et hotes intermediaires des maladies transmissibles dans le site du futur barrage hydroelectrique de Memve'ele. Il resulte des prospections entomologiques que les principaux vecteurs sont Anopheles gambiae et A. nili pour le paludisme; Simulium damnosum pour l'onchocercose; Glossina palpalis pour la trypanosomiase; Chrysops dimidiata et C. silacea pour la loase. Sur le plan malacologique; aucun hote intermediaire de schistosomiase n'a ete recolte. Le risque d'introduction de l'onchocercose; de la trypanosomiase et autres maladies vectorielles dans la region est discute en fonction des donnees ecologiques qui suivront la construction et la mise en eau du barrage. Des mesures visant a reduire les impacts negatifs sur la sante des populations sont preconisees

Impact des effluents d'un complexe agro-industriel sucrier sur la distribution des mollusques dulcaquicoles a Mbandjock (Cameroun)

Des prospections malacologiques ont ete entreprises dans la zone sucriere de Mbandjock (Cameroun). La discussion des mollusques est discutee suivant les types d'habitat. L'incidence des effluents du complexe agro-industriel (SOSUCAM) sur la faune malacogique est evaluee. En general; un faible degre de pollution est favorable a la faune malacologique alors qu'une forte pollution lui est nuisible. La presence de bulinus globosus est mise en evidence. Ce mollusque; hote intermediaire de schistosoma haematobium; etait absent lors des prospections anterieures. L'extension de bulinus globosus dans la localite devrait faire l'objet d'une surveillance a long terme

Determinants de la transmission de la bilharziose en zones amenagees dans les monts Mandara (Cameroun) : facteurs botaniques et malacologiques

Une etude de la transmission de la bilharziose a ete entreprise dans l'Extreme Nord du Cameroun. Les barrages de Ouro tada; de Douvar-Oudahay et de Ouazan ont ete etudies. Les facteurs malacologiques et botaniques ont ete evalues. Une polarisation des activites en fonction de la pente des berges de la retenue a ete observee. Les zones de faible pente sont les plus utilisees et correspondent aux sites privilegies par les plantes supportant les colonies de mollusques hotes intermediaires de schistosomiase. D'autres aspects de l'interaction homme-plantes aquatiques sont discutes