Asymptomatic carriage of malaria parasites in blood donors in Yaoundé.

BACKGROUND: Malaria can be transmitted through blood transfusion, but there is paucity of data concerning transfusion-transmitted malaria in Cameroun. OBJECTIVE: To determine prevalence of malaria infection and association with epidemiological and clinical data obtained from donors' responses. METHODS: Microscopic examination of stained thick and thin blood smears for the detection, quantification and specification of Plasmodium sp was performed on 493 blood donors in two main hospitals in Yaoundé during October and November 2007. RESULTS: Overall 6 · 5% of blood donors were detected positive for Plasmodium sp infection: 90 · 6% was Plasmodium falciparum and 9 · 4% was Plasmodium malariae. Parasite counts ranged from 80 to 800 µL(-1) with a median of 320 µL(-1). Asexual and sexual forms were found in 75 · 9 and 24 · 1% of cases, respectively. Age, sex, type of blood donor (voluntary non-remunerated vs familial/replacement) and fate of blood donation (selected vs discarded) did not affect the prevalence of malaria carriage. The lack of malaria prophylaxis as well as the manifestation of malaria symptoms within 2 weeks and 1 month preceding blood donation were significantly associated with high frequency of parasites carriage. CONCLUSION: Malaria parasites carriage is frequent among blood donors in Yaoundé. These data seem to describe high-risk donor profile and may help improving blood safety related to transfusion-transmitted malaria in Cameroon.

Serum lipid profile in highly active antiretroviral therapy-naïve HIV-infected patients in Cameroon: a case-control study.

BACKGROUND: HIV status has commonly been found to affect the serum lipid profile. OBJECTIVES: The aim of this study was to determine the effect of HIV infection on lipid metabolism; such information may be used to improve the management of HIV-infected patients. METHODS: Samples were collected from December 2005 to May 2006 at Yaounde University Teaching Hospital, Yaounde, Cameroon. Lipid parameters were obtained using colorimetric enzyme assays, while low-density lipoprotein cholesterol (LDLC) values were calculated using the formula of Friedewald et al. (1972) and atherogenicity index by total cholesterol (TC)/high-density lipoprotein cholesterol (HDLC) and LDLC/HDLC ratios. RESULTS: HIV infection was most prevalent in subjects aged 31 to 49 years. Most of the HIV-positive patients belonged to Centers for Disease Control and Prevention categories B (43.0%) and C (30.23%). Compared with control subjects, patients with CD4 counts<50 cells/microL had significantly lower TC (P<0.0001) and LDLC (P<0.0001) but significantly higher triglyceride (TG) values (P<0.001) and a higher atherogenicity index for TC/HDLC (P<0.01) and HDLC/LDLC (P=0.02); patients with CD4 counts of 50-199 cells/microL had significantly lower TC (P<0.001) and significantly higher TG values (P<0.001); patients with CD4 counts of 200-350 cells/microL had significantly higher TG (P=0.003) and a higher atherogenicity index for TC/HDLC (P<0.0002) and HDLC/LDLC (P=0.04); and those with CD4 counts >350 cells/microL had a higher atherogenicity index for TC/HDLC (P<0.0001) and HDLC/LDLC (P<0.001). HDLC was significantly lower in HIV-positive patients irrespective of the CD4 cell count. Lipid parameters were also influenced by the presence of opportunistic infections (OIs). CONCLUSION: HIV infection is associated with dyslipidaemia, and becomes increasingly debilitating as immunodeficiency progresses. HDLC was found to be lower than in controls in the early stages of HIV infection, while TG and the atherogenicity index increased and TC and LDLC decreased in the advanced stages of immunodeficiency.

The epidemiology of Plasmodium falciparum malaria in two Cameroonian villages: Simbok and Etoa.

In support of ongoing immunologic studies on immunity to Plasmodium falciparum, demographic, entomologic, parasitologic, and clinical studies were conducted in two Cameroonian villages located 3 km apart. Simbok (population = 907) has pools of water present year round that provide breeding sites for Anopheles gambiae, whereas Etoa (population = 485) has swampy areas that dry up annually in which A. funestus breed. Results showed that individuals in Simbok receive an estimated 1.9 and 1.2 infectious bites per night in the wet and dry season, respectively, whereas individuals in Etoa receive 2.4 and 0.4 infectious bites per night, respectively. Although transmission patterns differ, the rate of acquisition of immunity to malaria appears to be similar in both villages. A prevalence of 50-75% was found in children < 10 years old, variable levels in children 11-15 years old, and 31% in adults. Thus, as reported in other parts of Africa, individuals exposed to continuous transmission of P. falciparum slowly acquired significant, but not complete, immunity.

A randomized, double-blind study on the efficacy and safety of a practical three-day regimen with artesunate and mefloquine for the treatment of uncomplicated Plasmodium falciparum malaria in Africa.

A randomized, double-blind, parallel-group study in 104 hospitalized patients with acute, uncomplicated Plasmodium falciparum malaria was performed in West and Central Africa from March to July 2001. Patients were randomized to receive simultaneous dosing (artesunate 200 mg/d plus mefloquine 250 mg/d from the first to the third day [investigational group]) or sequential dosing (artesunate 200 mg/d for 3 d plus mefloquine 250 mg on the second and 500 mg on the third day [reference group]). Patients were followed-up for 28 d, and clinical and parasitological outcomes were assessed. The 14-d cure rate was 100% in the investigational group and 98% in the reference group with no recrudescence until day 28. Mean times to fever and parasite clearance were similar between the 2 groups (32 h vs. 26 h and 45 h vs. 48 h) and tolerability was good in both groups. The number of patients with vomiting was statistically significantly lower in the investigational group compared to the reference group (3.8% vs. 19.2%, P = 0.014). A 3-d once-daily co-administration of artesunate and mefloquine starting on day one offers a practical dosing regimen, which is highly effective and well tolerated in patients with uncomplicated P. falciparum malaria.

The contribution of existing health facilities to the control of urinary schistosomiasis in northern Cameroon.

This paper attempts to analyse the impact of the regular functioning of existing health services on the control of urinary schistosomiasis in two villages in northern Cameroon. The health centres' diagnostic systems selectively recognise heavy infections. The efficacy of reaching and subsequently treating heavily infected subjects, however, is low. No more than around 5% of the heavily infected subjects in the health centres' catchments areas is reached on an annual basis. Further analysis shows that the percentage of infected and heavily infected subjects is not higher among the visitors of the health centre than in the inhabitants of the villages involved. Heavy infection is not a reason to visit the health centre, in these villages. To increase the role of the existing health structure in coping with Schistosoma haematobium infections, the diagnostic system, used in the health centres, could be improved by a standardized inclusion of laboratory examination of clinically suspected individuals. Simultaneously, the awareness of the infected population to respond to infection by visiting the health centre needs further development.

[An epidemiological study of human filariasis : loaiasis, dipetalonemiasis, tetrapetalonemiasis, in Douala fisherman of the river Wouri estuary (Cameroon) (author's transl)]. / Etude épidémiologique des filarioses humaines : loase, dipetalonémose, tétrapétalonémose, chez les pêcheurs Douala de l'estuaire du Wouri (Cameroun).

The aim of the study is to establish the prevalence of loaiasis, dipetalonemiasis, tetrapetalonemiasis, with particular emphasis on T. streptocerca infection. Eight small villages located close to Douala in the mangrove area of the Wouri estuary are visited and 788 dermic scarification prints stained with Böhmer hematoxylin are examined. Microfilariae belonging to the species L. loa are found in 11,2 p. 100 of the prints, D. perstans mirofilariae are found in 23,2 p. 100 and T. streptocerca in 6,9 p. 100. The prevalence of filariasis and the parasitic load are higher in male than in female. The older the inhabitants are, the more heavily infected they are found. Except for pruritus and craw-craw associating a filarial infection with characteristic symptoms seems to be difficult in this study.

[Visceral leishmaniasis in Cameroon. Seroepidemiologic survey in the Kousseri region, north Cameroon]. / Leishmaniose viscérale au Cameroun. Enquête séro-épidémiologique dans la région de Kousseri, Nord-Cameroun.

A sero-epidemiological survey of school children was carried out in Kousseri, a focus for visceral leishmaniasis. Sero-immunological assays for the detection of anti-Leishmania antibodies were based on the indirect immunofluorescence assay test and counter-immunoelectrophoresis. 9 out of 223 school children tested positive for visceral leishmaniasis (seroprevalence rate of 4%). These 9 cases had no history of the disease. The data obtained confirm the endemicity of visceral leishmaniasis in this focus and call for extensive studies in order to determine the prevalence of the disease in the entire population as well as the main components of the transmission cycle.

[Variations under genetic control of onchocerca infection as a function of clinical profile in the endemic center of Cameroon]. / Variations sous contrôle génétique de l'infection onchocerquienne en fonction du profil clinique dans les foyers endémiques du Cameroun.

Onchocerciasis, also known as "river blindness", presents a plenum of clinical manifestations which vary from one individual to another, and from one area to another. This large spectrum of clinical manifestations of the disease is an indication of the complexity of the pathogenesis of onchocerciasis and suggests that many interacting factors might influence the clinical features of the disease. The present study has focused on the heterogenicity of the host immune response as a plausible explanation for differences in clinical manifestations of the infection. Host genetic factors, namely HLA genes, might play an important role in determining the nature of the immune response mounted against the parasite Onchocerca volvulus, and thus the development of different manifestations of the infection. Genetic diversity of onchocerciasis was assessed in different endemic foci in Cameroon. In order to investigate the possibility that the Major Histocompatibility Complex (MHC) genes might be associated with the different clinical types of onchocerciasis, 146 subjects living in three endemic areas of Cameroon were studied. They were classified in four groups: A (asymptomatic subjects), P (putatively immune subjects) L (patients with localised disease) and G (patients with generalised disease). The four groups differed in the distribution of HLA class II alleles as determined by Direct Heteroduplex Analysis. On the one hand, allele HLA-DQA1*0501 appeared to be associated with protection against severe onchocerciasis; on the other, allele HLA-DQB1*0201 might play an important role in the severe form of the disease.

[Candidiasis and AIDS in Yaounde]. / Candidoses et SIDA à Yaoundé.

In this preliminary study, we discuss 9 cases of Candidosis diagnosed during a 6 month period in 32 AIDS patients hospitalized in three health Centers in Yaoundé. Most of the patients presented with buccal candidosis and/or dysphagia. Of the 18 strains grown, 17 (94%) are Candida albicans.

[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.

[Experimental study of the compatibility between Schistosoma haematobium and two species of Bulinus in Cameroon]. / Etude expérimentale de la compatibilité entre Schistosoma haematobium et deux espèces de bulins au Cameroun.

A study on the compatibility between Schistosoma haematobium from three remote localities (Mourtourwa, Gounougou and Kékem) and four populations of Bulinus truncatus (Gounougou, Ngaoundéré, Bertoua and Kékem) and four populations of B. globosus (Mourtourwa, Ouroudoukoudje, Bafia and Yaoundé) was undertaken in order to estimate the risk of extension of urinary schistosomiasis in Cameroon. First generation of offspring from wild Bulinus was exposed to miracidia liberated by schistosome eggs extracted from patient urine. Between the 25th and the 60th day post-infestation the number of snails still alive, the number emitting cercariae and the prepatent period duration were noted. Results showed that all B. truncatus samples were susceptible to the three strains of parasite whereas only B. globosus of Mourtourwa and Ouroudoukoudje were susceptible to S. haematobium from Mourtourwa. The schistosome infection rate was then significantly higher in B. truncatus and the prepatent period significantly lower than in B. globosus. The compatibility characterised by a high infection rate and a low prepatent period was significantly better in homopatric couples than in allopatric combinations. The results suggested that B. truncatus might be potentially more implicated than B. globosus to the extension of the urinary bilharziasis in Cameroon.

[Morbidity and histo-endoscopic study of Schistosoma mansoni bilharziasis in Nkolbisson (Cameroon)]. / Morbidité et étude histo-endoscopique de la bilharziose a Schistosoma mansoni a Nkolbisson (Cameroun).

This study confirms the efficiency of bilharzia eradication campaigns at Nkolbisson. The authors recommend rectal mucosa biopsy of symptomatic patients in whom several investigations have turned out negative.

[Severe forms of malaria in children in a general hospital pediatric department in Yaounde, Cameroon]. / Les formes graves du paludisme de l'enfant dans un service de pédiatrie générale à Yaoundé, Cameroun.

Severe forms of malaria in children are responsible for 1 million deaths yearly in young children in hyperendemic areas. The main objective of this study was to identify and compare common manifestations of different forms of severe malaria and to evaluate the prognosis for hospital treatment in an endemic area. 271 files of children admitted into hospital between March 1991 and September 1996 were analysed. These children were confirmed to have Plasmodium falciparum in their peripheral blood. 78 patients (29%) had the severe form of malaria. 43 patients (53%) were under 5 years of age. The 5 severe types identified were characterized by very high temperatures 28 cases (36%), cerebral malaria 20 cases (26%), prostration and weakness 15 cases (19%), severe anaemia 14 cases (18%) and haemoglobinuria 1 case (1.3%). Cerebral malaria and severe anaemia were more common in children under 5 years old. The average parasitemia was 16,366 +/- 1390 parasites per microlitre. Clearance of parasitemia was obtained on day 3 in almost all cases; 6 patients with very high temperatures presented neither sign of visceral complications nor convulsions. The average period in coma for cases of cerebral malaria was 1.7 days; 12 anaemic patients were transfused. There were no deaths. No abnormality was found on physical examination after an average hospitalisation of 5.3 days. An early diagnosis and adequate treatment of severe forms of malaria in children by qualified personnel will usually result in a favourable prognosis in our area.

[Periportal fibrosis in Schistosoma mansoni schistosomiasis. An ultrasonographic study in the area of Nkolbisson (Cameroon)]. / Fibrose périportale dans la schistosomiase à Schistosoma mansoni. Une étude ultrasonographique dans le foyer de Nkolbisson (Cameroun).

PURPOSE: The appearance of Symmers' periportal fibrosis (SPF) is considered a major event in the natural history of Schistosoma mansoni infection, because of the risk of portal hypertension and subsequent intestinal hemorrhage. Ultrasonography has been found useful in the assessment of this lesion. We undertook the present study to determine the prevalence of SPF in Nkolbisson (near Yaoundé), where previous studies had shown Schistosoma mansoni infection to be endemic. METHODS AND MATERIALS: 147 patients more than 15 years old (mean age: 32 years) were prospectively studied during a 3 month period. 107 subjects (51 male, and 56 female) were excreting Schistosoma mansoni eggs in the stools (mean egg output = 336 egg/g), and 40 controls had a negative stool exam. A medical history, a physical examination, and an abdominal ultrasound examination were performed on each subject. The degree of SPF was graded according to Homeida's scale. RESULTS: 39 Subjects (24 male, 15 female) with positive stool examination had SPF giving a prevalence rate of 37%, while it was found to be 5% for controls. 28 patients had mild fibrosis (grade I), 7 patients had moderate fibrosis (grade II), and 4 patients had severe fibrosis (grade III). Higher prevalence rates of SPF were associated with longer duration of infection and very high egg outputs (> 1,000 egg/g). The positive predictive value of hepatomegaly or splenomegaly for the presence of SPF was 0.52, and the negative predictive value 0.69. CONCLUSION: We conclude that SPF affects a significant proportion of infected patients and ultrasonography is a valuable tool in the study of this lesion in our patients.

[Epidemiology of dracunculosis in the Mandara Mountains (North Cameroon). Organization of a control campaign]. / Epidémiologie de la dracunculose dans les Monts Mandara (Nord-Cameroun). Organisation d'une campagne de lutte.

The map of the Mandara Mountains dracuntiasis focus showing the wells and water bodies, which are the transmission sites of the disease in the study area, shows that the focus is relatively well limited. The drilling of new wells, the protection of existing water bodies used for human consumption, the health education project and the treatment of water by temephos lead to ascertain that the number of Guinea worm cases seen is decreasing every year in the area where the project is meticulously performed. These encouraging results show that it is now possible to eliminate the Guinea worm from North Cameroon by extending the operations in progress to the comprehensive surface of the focus, including the remote areas in mountains and the satellite foci in the plain along the Nigerian border.

[Rapid resolution of Plasmodium ovale malarial attacks using artesunate (Arsumax)]. / Resolution rapide des acces palustres à Plasmodium ovale par l'artésunate (Arsumax).

This randomized, non-comparative clinical trial without placebo was carried out to assess the efficacy and tolerance of artesunate for treatment of acute Plasmodium ovale malarial attacks. Thirty Cameroonese patients were included. All presented acute Plasmodium ovale malarial attacks with parasitemia in excess of 500 asexual forms per mm3. Four days after treatment with artesunate, all 30 patients were asymptomatic with no parasitemia. Reduction rates were 93.9 p. 100 for asexual forms and 75.4 p. 100 for gametocytes. Parasite clearance was achieved within 38.8 hours and fever disappeared within 36.6 hours. Tolerance was excellent in 29 patients. The remaining patient briefly complained of mild vertigo. A transient decrease in reticulocyte levels was observed in one patient initially presenting anemia. Artesunate appears to achieve rapid and complete resolution of acute Plasmodium ovale malarial attacks. Since artesunate eliminates both asexual forms and gametocytes, it also acts on transmission by limiting the duration of survival of asexual forms.

[Epidemiologic study of intestinal and urinary bilharziasis in the Tala Mokolo region (Mandara Mountains, North Cameroon)]. / Etude épidemiologique des bilharzioses intestinale et urinaire dans la région de Tala Mokolo (Monts Mandara, Nord Cameroun).

In the Mandara Mountains, where small dams have been erected, people living in the Tala Mokolo district eliminate some S. haematobium eggs in 31,4% of urines samples, and some S. mansoni eggs in 38,1% of stools samples. Evaluated from hemagglutination test, bilharziosis prevalence reaches 55,7%. Male subjects are more frequently affected than female subjects, particularly as for as intestinal bilharziosis is concerned. Urinary bilharziosis prevalence or intestinal bilharziosis prevalence are subject to proximity of small water reservoirs mostly infested either by Bulinus globosus or Biomphalaria pfeifferi. These small water reservoirs are mainly "mayo" head-bays.

[Epidemiologic study of malaria in the Koza region (North Cameroon)]. / Etude épidémiologique du paludisme dans la région de Koza (Nord Cameroun).

The data obtained in the survey carried out in the villages of the Mandara mountains are as follows. P. falciparum is the only species of Plasmodium which has been found in the area. The parasitic rate in children 2 to 9 years of age is 40.8 p. 100 and the spleen rate 35.6 p. 100. The immunofluorescent test performed with an homologous P. falciparum antigen is positive in 37.7 p. 100 of the children of this class of age. The thick drop shows parasites in 25 p. 100 of the newborn children. The parasitic load rated by number of blood cells harboring parasites is high in young children, then diminishing in adults while the antibodies increased. Malaria cases are more numerous at the end of the rainy season but a new spell of the disease is also noticed at the beginning of the year while the outside temperature is especially high. Malaria, now mesoendemic in the study area, seems to decrease as far as parasite and spleen rates are concerned in comparison with the rates obtained in the Mandara mountains 20 years ago. This seems to be a consequence of an increase in the intake of chloroquine by the inhabitants.

[Dynamics of intestinal schistosomiasis in Cameroon: evolution of transmission in the mixed zone of Nkolmébanga, Lékié]. / Dynamique des schistosomoses intestinales au Cameroun: évolution de la transmission dans le foyer mixte de Nkolmébanga, Lékié.

This study was undertaken to evaluate the current status of shistosomiasis in the Nkolmébanga region (Lékié) of Cameroon, previously determined to be a mixed zone harboring both Schistosoma mansoni and S. intercalatum. Study involved both malacology with collection and identification of freshwater snails in four waterpools and parasitology with collection and analysis of stools from schoolchildren. Five species of freshwater snails were identified including two that were intermediate host of Schistosomes, i.e., Biomphalaria pfeifferi and Bulinus forskalii. Only B. pfeifferi species collected from the Momboh and Mbonsoh Rivers shed Schistosoma cercaria. A total of 347 schoolchildren were enrolled but only 200 provided stools for parasitological testing. There were 93 boys and 107 girls. Parisitology demonstrated S. intercalatum eggs in the stools of no children. S. mansoni eggs were identified in the stools of 10 children for a prevalence of 5%. Parasitic load ranged from 24 to 1104 eggs per gram of stool. In this study both malacologic and parasitological findings suggested that S. mansoni persists in Nkolmébanga region but that S. intercalatum has disappeared probably as a result of deforestation and urbanization.

[Sensitivity of S. intercalatum to praziquantel (author's transl)]. / Etude de la sensibilité de S. intercalatum au traitement par le praziquantel.

The stools of 35 patients with S. intercalatum bilharziasis are examined 48 hours, 45 days and 6 months after treatment, using praziquantel, a new trematodicide drug, in an individual single dose of 40 mg/kg body weight. The number of eggs per gram of faeces is not significantly reduced 2 days after treatment. After 45 days however eggs are only to be found in the stool of one patient among the 25 treated persons who were seen for control. Six months later 23 persons were examined again and 3 stools specimens were found positive, this being possibly due to reinfection. The drug has been well tolerated, except for minor side effects such as headache, nausea and abdominal discomfort.