Epidemiology of malaria in a village of Sudanese savannah in Mali (Bancoumana). Anti-TRAP and anti-CS humoral immunity response

Vaccine development research is an important component of malaria control strategies. Thrombospondin related anonymous protein (TRAP) and the circumsporozoite (CS) protein are two antigens of sporozoite surface. Immune response to these two antigens may contribute to the development of anti-sporozoite vaccine. Recent studies suggest that antibodies anti-TRAP may partially block sporozoites penetration in hepatocyte, and thereby reducing malaria morbidity. We carried out a study to assess the seroprevalence of anti-TRAP and anti-CS antibodies and to identify a possible role of these antibodies on malaria morbidity in children 1-9 years old living in a rural hyperendemic village. We performed 5 cross sectional surveys and a longitudinal follow up in 1993 and 1994. During each cross sectional study, children were examined for fever and splenomegaly; all febrile children received thick film examination, and serologic analysis was performed in one third of these, randomly selected. The results show that the seroprevalence of anti-TRAP and anti-CS varied with age and season (p < 0.05). Association between the prevalence of anti-TRAP and splenomegaly was observed during two cross sectional surveys (June and October 1993). The presence of anti-TRAP antibody was associated with Plasmodium falciparum infection at the beginning of the transmission season (June 1993 and July 1994). A negative association between the level of anti-TRAP title and parasitemia was observed (March and October 1994). These findings suggest no clear evidence of the protective role of anti-TRAP antibodies in uncomplicated malaria, possibly due to the limited persistence of these antibodies under natural situations.     

Evaluation and treatment of snake bites in Bancoumana village in Mali

A retrospective study was conducted on the epidemiological patterns and treatment of snakebites in the village of Bancoumana, 60 km south-west from Bamako. We analysed a total of 17 cases (8 males and 9 females). The distribution of snakebite cases by gender and by age showed that among subjects aged 5 to 20 years, boys were more exposed than girls (6 vs. 2), whereas, in those of 21 years and above, females were more frequently bitten than males (7 vs. 2) (p = 0.04). The treatment was mainly based on the use of anti-inflammatories and antibiotics, and sometimes of saline, glucose or anti-tetanic serum. Vitamin K was used in 7 cases and no patient was treated specifically. The success of therapy mostly depended on the shortness of delay between the snakebite occurring and patient referral to the health centre, and the low rate of envenomation. All the patients referred the same day they were bitten were cured, whereas three persons referred to the health centre at D3, D7 and D43 after bite died. The surveillance parameters were oedema, bleeding and vomiting.     

A comparison of 2 capture methods for sampling the population of Anopheles funestus Giles in a Sudanese savannah village (Dielmo,Senegal)

We conducted a comparative study of two collection methods for sampling An. funestus populations--human bait catch and indoor pyrethrum spray--in the Sudanese savannah area of Senegal from April 1996 to March 1997. An. funestus females were captured every month during the study period. The resting density per dwelling was 1.9 times higher than those obtained with human landing catch. The population dynamics were similar with two peaks situated respectively at the beginning of the rainy season between May-July and during the dry season January-March. A significant correlation of population densities between collection methods was detected.     

Urban malaria in Yaounde (Cameroon). 2. Entomologic study in 2 suburban districts]

A one year entomological survey was carried out to precise the malaria vectors and the malaria transmission in Yaounde, the Cameroon capital (800,000 inhabitants). The study was done in two districts not yet fully urbanized: Nkol Bikok and Nkol Bisson. The latter is located at the periphery and has a pool. Anopheles gambiae was the only human malaria vector. Its agressivity for man depended on the urbanization of the district. Annual man biting rate was 284 in Nkol Bikok and 1,813 in Nkol Bisson. The densities were maximum in May-June and in October-November, corresponding to the end of the short and long rainy seasons. The presence of A. gambiae was permanent except in August-September in Nkol Bikok. In Nkol Bisson the density was higher in the houses near the pool. The yearly inoculation rate (h) was 14 in Nkol Bikok and 30 in Nkol Bisson. The vectorial transmission was observed in may in Nkol Bikok and during four months (June, August, January, February) in Nkol Bisson. These entomological data showed clearly that malaria transmission actually occurred in Yaounde and that the probability to receive at least one infected anopheline bite per year was very near to 1 for inhabitants unprotected against mosquito bites.     

Epidemiology of equine herpesvirus 2 (equine cytomegalovirus).

The epidemiology of equine herpesvirus 2 was examined by using restriction endonuclease DNA fingerprints to distinguish viruses isolated from two groups of horses. The first group consisted of three yearlings isolated from other horses but in contact with each other for 418 days, whereas the second comprised seven mares and their foals, which were sampled at monthly intervals from parturition until the foals were about 180 days old. There was a complex pattern of transmission, with 15 different viruses isolated from both groups. Four distinguishable viruses were isolated from the three yearlings by day 16 of quarantine, and by day 141 an additional two viruses were isolated. Up to five different viruses were isolated from one yearling. Although four repeat isolations of one virus from the nasal cavity of one yearling over 54 days indicated that equine herpesvirus 2 established persistent infection with constant shedding, most repeat isolations yielded distinguishable viruses. Identical viruses were isolated from the nasal cavity and leukocytes of one yearling and the nasal cavity and vagina of another, indicating that a particular equine herpesvirus 2 strain was not site specific. Although seven different viruses were isolated from the three yearlings throughout the quarantine period, two appeared to establish latent infections; one virus was not isolated until 141 days after quarantine, whereas the second was first isolated 16 days after quarantine and then for the second time, from the same horse, 402 days later. Multiple concurrent local infections were demonstrated by the isolation of two or more viruses from the same nasal swab.     

Glucose-6-phosphate dehydrogenase deficiency in Mali. Epidemiology and pathological aspects

I,858 semi quantitative G6PD determinations were done in Mali (mostly in the Point G Hospital, in Bamako). 15.7% of the men and 4.5% of the women had a G6PD deficiency. The age did not affect the incidence of the disease. G6PD deficiency was more frequent among the Sonrais than among the other ethnic groups tested. It did not occur more frequently among subjects having the sickling trait of AC hemoglobinopathy but no G6PD was found among subjects having a major hemoglobinopathy (SS or SC). Severe hemolytic anemia was rather infrequent among adults subjects. Hemolysis was induced by drugs--such as dapsone or niridazole--but it was usually mild and time-limited.     

High malaria transmission intensity due to Anopheles funestus (Diptera: Culicidae) in a village of savannah-forest transition area in Cameroon

An entomological survey was conducted on vectors of malaria in a village of the forest-savannah transition area in Cameroon from February 1999 to October 2000. A total of 2,050 anopheline mosquitoes belonging to eight species were caught 1) after landing on human volunteers, 2) by using pyrethrum spray collections in human dwellings, and 3) in resting sites outdoors. Anopheles funestus Giles was the most abundant species (accounting for 91% of anophelines caught) followed by Anopheles gambiae Giles (7%). Applying polymerase chain reaction led to the identification of all specimens of the An. funestus group as An. funestus sensu stricto and mosquitoes from the An. gambiae complex were mostly An. gambiae sensu stricto of the S molecular form. Malaria transmission was perennial with an entomological inoculation rate estimated at 172 infective bites per person during the period of study. An. funestus was responsible for 88% of the total malaria transmission, with a Plasmodium falciparum circumsporozoite rate of 6.8% and an anthropophilic rate of 99.3%. These results confirm that in high agricultural activity areas, An. funestus can be, by far, the major malaria vector.     

Survivorship and distribution of immature Anopheles gambiae s.l. (Diptera: Culicidae) in Banambani village, Mali

We observed the survivorship and distribution of larvae and pupae of Anopheles gambiae s.l. Giles immature stages in three habitats (rock pools, swamp, and puddles) in Banambani village. Mali, West Africa, during the mid-rainy season of 2000. Horizontal life tables were constructed for immatures in the laboratory. Times spent in the various immature stages were determined, and laboratory survival was measured. Vertical life tables were obtained from each habitat. We found large day-to-day variation for age class composition within habitats across days. The swamp samples had small but statistically significant different distributions in some instar stages compared with rock pools and puddles as affected by precipitation history. There were obviously unstable age distributions in the swamp and puddles and to some extent in rock pools. There were more individuals in some later age classes than in earlier ones. The daily survival estimates using an exponential decay model were 0.807 in rock pools, 0.899 in the swamp, 0.818 in puddles, and 0.863 in the overall village. Possible reasons for the departure from stable age distribution were cannibalism, predation and other complex interactions, rainfall effects, sampling bias, and differences in physicochemical properties of the water in the habitats.     

Sociocultural dimension of epilepsy (kirikirimasien) in a Bambara rural area (Mali)

The anthropological study of kirikirimasien (epilepsy) in Mali constitutes an integral part of a research programme devoted to the epidemiology of epilepsy and onchocerciasis in Mali. This programme is run jointly by scientists of the Ecole Nationale de Médecine et de Pharmacie (National School of Medicine and Pharmacy) of Bamako, Mali, and the Faculté de Médecine (Faculty of Medicine) of Marseilles, France. Preliminary results of the anthropological study are presented, based on the qualitative analysis of 132 interviews, conducted over 6 months. Those interviewed were mainly persons affected by kirikirimasien, but included members of the family circle, traditional healers, and outsiders as well. Participatory interview techniques used the national language bambara. The interviews were unstructured and semi-structured so as to identify themes in the bambara language concerning kirikirimasien. Two dominant trends were identified, concerning the aetiology and nosography of the disease, and the social dimension of kirikirimasien, respectively. In terms of aetiology and nosography, diagnosis, contamination and appelation are--in order of priority--the most important aspects of the disease. Yet the social dimension of kirikirimasien appears largely to surpass its aetiological and nosographic aspects. The social dimension is crucial to the anthropological understanding of kirikirimasien. This was amply illustrated by various references which arose during the interviews. First, how is the notion of contamination represented and which practices are associated with it? Second, invalidity and handicap appear to play an essential role in the way people deal with the disease. The notion of tolerance in the bambara environment is also addressed, mainly through a spatial study of the adherence of the person affected by the disease (family, village and outsiders). The third part of the study deals with the social understanding of kirikirimasien and looks at how those affected are cared for, both within their social setting and in terms of seeking treatment.     

Anopheles funestus (Diptera: Culicidae) in a humid savannah area of western Burkina Faso: bionomics, insecticide resistance status, and role in malaria transmission

An entomological survey was carried out in three humid savannah sites of western Burkina Faso (Bama, Lena, and Soumousso) to (1) update the taxonomy of the Anopheles funestus Giles group, (2) examine the role of each species in malaria transmission, (3) characterize the insecticide resistance status of this malaria vector, and (4) determine the distribution of An. funestus chromosomal forms in these areas. Polymerase chain reaction identification of the members showed the occurrence of An. leesoni Evans in Lena and An. rivulorum-like in Soumousso in addition to An. funestus s.s. Malaria transmission was ensured mainly by An. funestus s.s. both in Soumousso and Lena and by An. gambiae s.s. Giles in Bama, the rice-growing area. The insecticide resistance status performed only on An. funestus indicated that this mosquito was susceptible to pyrethroids irrespective of the study area, but it was resistant to dieldrin. Furthermore, the occurrence of the two chromosomal forms of An. funestus, namely, Kiribina and Folonzo, seemed to follow ecological setups where Kiribina predominated in the irrigated area and Folonzo was more frequent in classic savannah. This study revealed that the problematic of An. funestus taxonomy was closer to that of An. gambiae requiring more structured studies to understand its genetic ecology.     

Nasal Carriage of Staphylococcus aureus and Epidemiology of Surgical-Site Infections in a Sudanese University Hospital

Surgical site infections (SSI) due to Staphylococcus aureus among 256 male and 158 female patients (mean age, 28 years) undergoing elective surgery at the Soba University Hospital (Khartoum, Sudan) were studied. During an 11-month study period all patients were analyzed for nasal carriage of S. aureus at the time of admission. Follow-up of the development of SSI proceeded until 4 weeks after the operations. In addition, nasal swabs were obtained periodically during the same period from 82 members of the staff. In order to discriminate autoinfection from cross infection, bacterial isolates were typed by random amplification of polymorphic DNA (RAPD), pulsed-field gel electrophoresis (PFGE) of DNA macrorestriction fragments, and restriction fragment length polymorphism analysis of the protein A and coagulase genes. Preoperative cultures revealed the presence of S. aureus in the noses of 98 patients (24%). The overall number of postsurgical wound infections in the entire group was 57 (14%), 24 of which were due to S. aureus. Only 6 of the 98 nasal S. aureus carriers suffered from wound infections by the same species. In these six cases the infecting strain could not be genetically discriminated from the nasal inhabitant, substantiating autoinfection. However, nasal carriage of S. aureus is not a significant risk factor for the development of SSI in this setting (6 of 98 patients with autoinfection versus 18 of 316 patients [414 − 98 patients] with cross infection; P = 0.81), most probably due to the fact that noncarriers are at a significant and relatively large risk for acquiring an independent S. aureus SSI. The other S. aureus strains causing SSI showed a high degree of genetic heterogeneity, demonstrating that it is not an epidemic strain that is causing the SSI. Among the staff personnel screened, 47.4% did not carry S. aureus in the nose at any time during the study period, whereas 13.2% persistently carried a single strain in the nose. Another 39.5% could be classified as intermittent carriers. When strains derived from staff personnel were genetically typed, it was demonstrated that most of the strains represented genetic variants clearly differing from the isolates causing SSI. On the other hand, possible cross colonization among staff personnel and even cross infection from staff personnel to patients or from patient to patient were demonstrated in some cases, but epidemic spread of a single strain or a few clonally related strains of S. aureus could be excluded.Major waves of infectious agents have to be battled on the African continent. One of these agents is the bacterium Staphylococcus aureus. It has been documented, for instance, that 3 to 4% of all surgical admissions in tropical countries concern drainage of pyomyositic infections (2). On the order of 50% of these abscesses, generating 30% mortality if untreated, are caused by a staphylococcal infection (17). Advanced stages of AIDS seem to predispose patients to the development of intramuscular abscesses caused by S. aureus as well (2). S. aureus has also been implicated as a causal organism in various other diseases in the tropics. High percentages of neonatal sepsis are due to S. aureus (6), and strains that are isolated from blood in rural Africa are generally penicillin resistant and often resistant to other antibiotics as well (21). A recent study performed in hospitals in Mogadishu, the capital of Somalia, demonstrated the presence of multidrug-resistant S. aureus strains; a surprisingly high level of methicillin resistance due to overproduction of β-lactamases was documented (20). Multiple studies have demonstrated that on the order of 40% of all clinically evident cases of persistent middle ear effusion in otitis media are due to S. aureus (5, 19). A recent Nigerian study demonstrated that S. aureus can coexist in a clinically manifest fashion with paramyxoviruses causing acute bronchiolitis (13). Thus, it is obvious that S. aureus has a major clinical impact on the African continent. The recent emergence of relatively high percentages of methicillin-resistant strains (10) and the poorly controlled distribution and inappropriate use of antibiotics may aggravate these problems in the coming years.In contrast to the African situation, in developed countries S. aureus is mainly encountered as an opportunistic and nosocomial pathogen. Various reports confirmed that nosocomial infection with S. aureus is an important cause of morbidity and mortality among hospitalized patients in western European countries and the North American continent (7, 12). Surgical site infections (SSI) caused by S. aureus are an important complication of surgery. A considerable amount of medical literature showed that S. aureus appears to be the major pathogen involved in SSI, and a main risk factor for the development of SSI was proven to be S. aureus nasal carriage (4, 15). SSI is a common problem in the Sudan as well, although only a limited number of studies to unravel the local microbial epidemiology have been undertaken up to now (1, 8). The aim of the present study was to assess the role of nasal S. aureus carriage among patients and staff personnel in the development of SSI in the surgery department of a large teaching hospital in Khartoum, the capital city of Sudan.     

In vitro and in vivo evaluation of a new polysulfone membrane for hemodialysis. Reference methodology and clinical results. (Part. 2: in vivo study).

Different high flux membranes have been recently developed. The present study is aimed at describing the technical features and the clinical performances of a new high flux polysulfone membrane (T-sulfone, Toray, Japan). The study has been carried out on two different dialyzers (surface area = 1.3 and 1.8 m2). The filters have been tested in vivo during hemodialysis and hemodiafiltration. The in vivo study was carried out on 12 ESRD patients on regular hemodialysis treatment. The protocol was reviewed and approved by the local ethical committee. The in vivo clearances (K) at 300 ml/min of blood flow are reported in the following Table: [Table in text]. Beta-2-m reduction ratio exceeded 50% in all sessions. Beta-2-m mass balance executed by collection of spent dialysate and elution from the used filters evidenced that removal is obtained mostly by filtration while absorption is negligible. Excellent tolerance and hemocompatibility was observed in all the studied sessions.     

Epidemiologic aspects of whooping cough in a village of the central district of Kolokani in Mali]

Epidemiologic aspects of a whooping cough outbreak are studied in a village of a rural precinct of Kolokani in Mali. The survey shows that the village as been contaminated by two children coming from Bamako, an urban center. Spreading of the epidemic is due to the lack of suitable therapy and vaccination. Seventeen cases are noticed within 83 children aged 0 to 13 years (20.5%) from October 12th, 1988, to January 22nd, 1989. The attack rate is the same in males and females. Knowledge, attitudes and practices of the population to face whooping cough are noted. Measures are proposed for therapy and prevention.     

Retrospective study of 1,934 cases of strongyloidiasis diagnosed in Paris (1970-1986). I. Geographic origin. Epidemiology

The geographic origins of the 1,934 strongyloidiasis cases were as follows: 1,211 cases originated from the West Indies, most of whom resided in France. From 1973 to 1986 the prevalence decreased from 47 to 30% for men, and from 30% to 17% for women. 433 cases originated from other intertropical countries, 257 of which were from 4 prevalence zones of Africa: 4.5% Mauritania, Mali, Niger; 9% Senegal, Burkina Faso, Togo, Za?re; 23% Guinea, Nigeria, Congo, Cameroon; 32% Ivory Coast, Gabon. 235 cases were French who had live, fought or travelled abroad (mainly Indochina and Africa). 33 Europeans of rural origin, infected in their country (2 in France?). 8 French cases infected in France (2 in Spain or Italy?).     

Spatial and habitat distribution of Anopheles gambiae and Anopheles arabiensis (Diptera: Culicidae) in Banambani village, Mali

We studied the larval distribution and composition of Anopheles arabiensis Patton, An. gambiae s.s. Giles, and its forms, among local habitats; and their association with the adults between these habitats in Banambani village, Mali during the mid-rainy seasons of 1997-1999. For species and form identification we used polymerase chain reaction (PCR) and PCR-restriction fragment-length polymorphism (RFLP). Differences among species in the distribution of larvae were observed in 1998, but not in 1997 or 1999, although they were on the borderline of statistical significance. Differences among the M and S molecular forms were statistically significant in 1999 when rainfall was high, but not in the two prior, drier sampling periods. Combining all information into the Fisher multiple comparisons test, there were statistically significant differences between species and molecular forms during the 3-yr study period. Hybrid larvae between the M and S forms were observed (0.57%), the first such observation to our knowledge. In spite of differences among larval distribution, no differences of adult species composition were observed among habitats. Factors that influence the distributions of An. gambiae larval populations are discussed.     

Epidemiology of salmonellosis in Caltagirone area (Sicily)

The authors report the results of an epidemiological-clinical study concerning episodes of salmonellosis observed in Caltagirone (CT) from 1999 to 2002 and reported to the National Centre for Control of pathogen enterobacteria (enter-net Italy). Overall, two hundred and forty strains of salmonella were isolated, typed and in vitro tested for susceptibility to eleven different antibiotics. Cases were evaluated according to patients' age, risk factors and clinical findings. Salmonella enteritidis (39%) was the most prevalent serovar followed by S. typhimurium (16%), S. newport (6%), S. salamae (5%) and others. The highest rate of antibiotic resistance was observed in S. typhimurium.     

Reversal of type 2 diabetes in mice by products of malaria parasites. II. Role of inositol phosphoglycans (IPGs).

We have previously shown that infection with Plasmodium yoelii malaria or injection of extracts from malaria-parasitized red cells induces hypoglycemia in normal mice and normalizes the hyperglycemia in mice made moderately diabetic with streptozotocin. Inositol phosphoglycans (IPGs) are released outside cells by hydrolysis of membrane-bound glycosylphosphatidylinositols (GPIs), and act as second messengers mediating insulin action. The C57BL/Ks-db/db and C57BL/6J-ob/ob mice offer good models for studies on human obesity and Type 2 diabetes. In the present study, we show that a single iv injection of IPG-A or IPG-P extracted from P. yoelii significantly (P < 0.02) lowers the blood glucose in STZ-diabetic, db/db, and in ob/ob mice for at least 4--6 h. Using rat white adipocytes, IPG-P increased lipogenesis by 20--30% in the presence and absence of maximal concentrations of insulin (10(-8) M) (P < 0.01) and stimulated pyruvate dehydrogenase (PDH) phosphatase in a dose-related manner. Both IPG-A and IPG-P inhibited c-AMP-dependent protein kinase (PKA) in a dose-related manner. Compositional analysis of IPGs after 24 h hydrolysis revealed the presence of myo-inositol, phosphorus, galactosamine, glucosamine, and glucose in both IPG-A and IPG-P. However, hydrolysis of IPGs for 4 h highlighted differences between IPG-A and IPG-P. There are some functional similarities between P. yoelii IPGs and those previously described for mammalian liver. However, this is the first report of the hypoglycemic effect of IPGs in murine models of Type 2 diabetes. We suggest that IPGs isolated from P. yoelii, when fully characterized, may provide structural information for the synthesis of new drugs for the management of diabetes mellitus.     

Species-specific PCR detection of malaria parasites by microtiter plate hybridization: clinical study with malaria patients.

A simple and convenient PCR method that amplifies the 18S rRNA genes has been developed for the purpose of detecting and differentiating four species causing malaria in humans. The advantage of the assay is that the biotinylated PCR product is visualized following hybridization with specific probes which are immobilized on plate wells (microtiter plate hybridization). This method has been previously evaluated in a field study and was found to be sensitive and specific for the detection of Plasmodium falciparum and Plasmodium vivax. In the current study, the microtiter plate hybridization PCR method was evaluated by using blood specimens from malaria patients. All of 36 cases of falciparum malaria, 26 of 27 cases of vivax malaria, all of 11 cases of ovale malaria, and 2 cases of malariae malaria were diagnosed species specifically by the PCR method. There were four smear-negative, PCR-positive cases that seemed to correspond to the convalescent stage of malaria. In contrast, 30 cases for which the diagnosis of malaria has been excluded on the basis of microscopy and clinical courses showed negative PCR results. By comparing parasite densities and PCR results following antimalarial treatment of some patients, it was revealed that the PCR results largely paralleled the parasite densities and that PCR could detect as few as 10 parasites per microliter of blood. We conclude that this PCR method is highly sensitive and specific for the detection of all four parasite species and can serve as a useful supplement to microscopy for the clinical management of malaria.