Bacteriological and clinical aspects of Salmonella typhi infections in the Central African Republic. Evaluation of a 3-year study in Bangui

Authors have isolated and identified 229 strains from patients with typhoid syndrome . The bacteriology of each strain was studied. We have observed the extension of A (subtype Dakar) lysotype to Central Africa from West Africa. All the strains are resistant for G penicillin. Clinical features are quite the same as in mild countries, with a high incidence in children. The typhoid fever is frequent and precocious in CAR, where prophylaxis by vaccination is not usual.     

Prospective study of enteric Campylobacter infections in children from birth to 6 months in the Central African Republic.

A survey of enteric Campylobacter infections was performed in Bangui, Central African Republic, with a cohort of 127 children from birth to 6 months of age by biweekly culture of stools; 82 infections were observed, and 41.7% of the children presented at least 1 infection before 6 months of age. Only 15.9% of the infected children had a diarrheic syndrome; moreover, 61.5% of these diarrheic children had another enteropathogen associated with Campylobacter species. In about half the cases, Campylobacter spp. were excreted for more than 4 days. More than half of the children had at least one diarrheic episode, for which an enteropathogen was identified in one third of the cases, before 6 months of age.     

Hemoglobinoses and hemoglobinopathies in the Central African Republic. 2]

Part of an inquiry which took place in R. C. A. from january 1972 to january 1975, we are able to give results concerning the prevalence of haemoglobin S in three new prospected regions and the value of sickling test. Cellogel electrophoresis sorted 20 0/0 of haemoglobin S bearers (AS or SS) od of 527 school children. On the same lot, sickling test by field practice, revealed only 7 0/0 and on the whole lot of examined individuals (684) only 8 0/0. This confirms that sickling test, when alone, is not reliable enough to appreciate the prevalence of haemoglobin S.     

Ecology of tick-borne arboviruses in the Central African Republic

Ticks have been collected on cattle skins for seven consecutive years in Bangui, Berberati, Bangassou and Bouar. 150 strains of arboviruses have been isolated from the four following species: Amblyomma variegatum: Dugbe, Jos, Thogoto, Crimean-Congo Hemorragic Fever (CCHF), Yellow Fever, Bhanja and Pétévo; Boophilus annulatus: Dugbe, Jos and Thogoto; B. decoloratus: Dugbe, Jos, Thogoto and CCHF; Hyalomma nitidum: CCHF. Dugbe (112 isolated strains), Jos (19 isolates) and Thogoto (11 isolates) viruses represent more than 95% of all the strains. Dugbe virus was isolated mostly during the first half of the rainy season. Jos virus shows a maximum rate of infection during the dry season (february) and a second peak in october (2nd half of the rainy season). Most of the strains of Thogoto virus have been isolated during the dry season. These seasonal variations of infection rates follow the seasonal variation of vector population densities. Thus preimagines and imagines of A. variegatum, the main vector of the Dugbe virus in C. A. R. show peaks of abundance respectively during the dry season and during the first half of the rainy season. Adults of Boophilus show maximum densities from december to february (dry season) when the greater number of Jos and Thogoto viruses are isolated. CCHF virus ecology needs more studies in Central African Republic. The importance of ticks in the wild cycle of Yellow Fever virus is not yet understood. Bhanja virus has been isolated only one time in C. A. R. Pétévo is a lately described virus which belongs to a group thus far unknown in Africa (Palyam gr.).     

Increase of HIV-1 subtype A in Central African Republic.

The concomitant presence of five distinct HIV-1 subtypes and of unclassified HIV-1 was reported in Bangui, Central African Republic (C.A.R.) between 1990 and 1991. This previous study was conducted in individuals belonging to the C.A.R. Armed Forces (FACA) Cohort and in patients from the University Hospital of Baugui. To follow the HIV-1 subtype distribution in Bangui over time, we conducted a cross-sectional surveillance of HIV-1 subtypes between 1987 and 1997 in three groups of individuals in Bangui: 47 men belonging to the FACA Cohort, 38 patients from the CNHUB hospital, and 51 individuals consulting the sexually transmitted diseases (STD) clinic. One hundred and ten HIV-1 were subtyped by heteroduplex mobility assay (HMA) and/or sequencing of env regions encompassing the V3 domain. By comparing the HIV-1 distribution in two time periods (1987-1991 and 1991-1996) in the FACA cohort, we observed a significant increase of subtype A from 43.7% to 83.9%. This subtype distribution does not seem specific to the FACA cohort, in that subtype A accounted for 46.7% of the HIV-1 infections in CNHUB patients in the first time period studied and for 69.6% in the second time period. In STD patients, subtype A infections were predominant in 1995 (72.7%) and 1997 (89.7%). Subtype E viruses could be identified in the second time period, but represented only between 6.5% and 21.8% of the infections in the three groups of individuals studied. Other subtypes (B, C, H) and non-classified HIV-1 in C2-V3 were detected with only a 3.2% to 9.1% frequency for each in the second time period. Phylogenetic analysis excluded infection by a single source for the individuals included in the study. Our data demonstrate an increase in the proportion of HIV-1 subtype A infections in Bangui that raises the question of a preferential transmissibility of specific HIV-1 variants.     

Isolation of the Lagos-bat virus in the Central African Republic

The second reported isolate of Lagos-bat virus has been obtained from bats Micropterus pusillus caught in 1974 in the Central African Empire, thus extending the geographic area of this virus and adding another species of vertebrate host among its reservoirs.     

Toxoplasmosis in the Central African Republic: first survey

For this purpose, toxoplasma antibodies were determined by latex agglutination test. Two kinds of human sera were examined: people in "good health" from North of Centrafrican Republic and patients from Bangui. In North, 40% of sera gave positive results and young girls from 1 to 14 years old seem to become positive earlier than young boys. At Bangui, 81% of sera from pregnant women coming from Medical Service was positive; all from 8 patients with ocular affections was positive and only 5 on 10 with adenopathy.     

Toxoplasmosis in the Central African Republic. Complementary study in a rural area

The epidemiological survey on the incidence of toxoplasmosis in rural areas of Central African Republic was carried out on a healthy population. The 814 samples came from 5 regions with 4 different climates. About 40% of the adults had IgG antibodies against Toxoplasma gondii except in pre-desert area where only 25% were positive. Girls became positive earlier than boys, but there was no difference between adult men and women except in pre-desert zone where men were more positive.     

Heterophils are decisive components in the early responses of chickens to Salmonella enteritidis infections

Chickens injected with 5-fluorouracil (5-FU) were found to have a three- to nine-fold reduction in circulating heterophils without a reduction in the number of circulating mononuclear cells. A 50% organ invasive dose (ID₅₀) for orally and intravenously administered Salmonella enteritidis (SE) was established in the heteropenic chickens. When challenged orally, about 150-fold fewer SE cells were required for organ invasion in the 5-FU-treated chickens; whereas an intravenous challenge of the heteropenic chickens required about 400g-fold fewer bacteria for organ invasion than found in the control birds.Significant (P < 0.0001) SE-dose-dependent reductions in body weight with increased mortality and lesions in the eye, heart, and thymus were found in the 5-FU-treated birds versus the control birds. Alternatively, the control birds had significantly more intestinal lesions than the 5-FU-treated birds. No consistent significant hepatic lesions were observed in either treatment group. Under the conditions used in these experiments, 5-FU treatment of chickens caused otherwise subclinical SE infections to rapidly become clinical infections with more severe extraintestinal organ infections, whereas the control chickens had infections that were primarily restricted to the intestine. These findings suggest that the heterophil is extremely important in controlling both initial SE organ invasion and subsequent disease pathogenesis in chickens.     

Rift Valley Fever and phleboviroses in the Central African Republic

During 1984 and 1985, six Rift Valley Fever virus strains (RVF) were isolated in Central African Republic, among them five from human samples. Three strains were isolated in 1985 at the end of the rainy season, from sera of patients dead with severe jaundice with haemorrhagic syndrome, what could evoke a little outbreak. At this occasion, these RVF strains and the other strains of phleboviruses previously isolated in CAR, were antigenically compared by Immuno-fluorescent assay (IFA) and Complement Fixation Test (CF), using mice immuno ascitic fluids prepared against each strain. A lot of cross reactions were noted between the different strains, but all the RVF strains seem to have the same antigenic outline.     

Monkey pox virus infection in humans in the Central African Republic

A human monkeypox outbreak is reported which occurred in January 1984 in the extreme south-west areas of the Central African Republic. Six persons were found to be affected in a Pygmy camp with an estimated population of 50 residents. In the two affected families, out of 11 members, only unvaccinated children and a 22 year old unvaccinated woman contracted the disease. The disease was of moderate severity in two patients and very mild in the other four. The clinical diagnosis was confirmed by virus isolation from skin lesions of 4 patients and by sero-immunologic tests in all of them. The clinically apparent monkeypox case reported in the Central African Republic in 1983, the presently described outbreak, as well as information on the disease obtained from Pygmies and missionary paramedical staff who are in frequent contact with them, suggest that monkeypox is enzootic in the tropical rain forest in the south-west areas of the Central African Republic.     

Phage typing of Salmonella enteritidis in the United States.

The number of reported isolates of Salmonella enteritidis has increased dramatically in the last 10 years. For many years phage typing has been a useful epidemiologic tool for studying outbreaks of S. typhi and S. typhimurium. In 1987, Ward et al. (L. R. Ward, J. De Sa, and B. Rowe, Epidemiol. Infect. 99:291-294, 1987) described a phage typing scheme for S. enteritidis. This system differentiated 27 phage types by use of 10 typing phages. With these phages, we typed 573 strains of S. enteritidis from humans (42 outbreaks), animals, food, and the environment. Ninety-six percent of the strains were typeable. The most common phage types were 8 (48.2%), 13a (20.1%), 13 (7.8%), and 14b (7.8%). Most of the strains were specifically collected from egg-related outbreaks in the northeastern United States in 1988 and 1989, probably accounting for the distribution of the four most common types in this sample. This system was particularly useful for differentiating a group of animal strains that had a number of diverse phage types. For 49 animal strains typed, 16 different patterns were obtained. Phage type 8 represented 32% of these strains, but no other phage type represented more than 8% of these strains. One-half of the 16 animal strains that were phage type 8 were from poultry. This phage typing system will be useful for comparing phage types found in the United States with those types encountered worldwide and for determining whether virulent strains of phage type 4 are entering the United States. Additional phage typing systems as well as molecular techniques are being studied to determine whether they can differentiate strains of phage types 8 and 13a.     

Serological approach to the occurrence of rickettsioses in the Central African Republic

A serosurvey for evidence of human rickettsial infections was carried out in the Republic of Central Africa on 144 sera by indirect immunofluorescence (IIF) and microagglutination tests (MA). There was no serological evidence of epidemic typhus and only two sera were positive for murine typhus. Approximately 15% of the surveyed population was serologically positive by MA for R. conorii antibodies. However, 48% of this population had spotted fever group antibodies as detected by IIF but were negative in MA for R. conorii, R. rickettsii and R. akari antibodies. These sera with high titers in IIF and negative in MA lead us to believe that in Central Africa there are rickettsiae pathogenic for man that are related to the Spotted Fever group and are yet to be identified.     

Neurologic and psychiatric manifestations of AIDS in Central African Republic

To describe and evaluate the frequency of neurological and psychiatric manifestations in African patients with AIDS, 93 in patients at the National Hospital Center, Bangui, were chosen according to the WHO clinical definition of AIDS and were confirmed to be HIV-1 positive (92/93) or HIV-2 positive (1/93) by Western blot. Patients were given both neurologic and psychiatric examinations. Cortico-spinal fluid (CSF) analysis was performed in case of neuro-psychiatric signs. 11 patients presented neurologic symptoms: 5 had focal processes associated in 2 cases with deep coma, 4 had cryptococcal meningitidis, 1 demonstrated peripheral facial paralysis, and there was one case of abnormal movement, choréo-athétotic type. 4 patients presented frank psychiatric symptoms (3 dementia syndromes, one of whom was HIV-2 positive, and 1 case of hallucinatory psychosis). CSF analysis was only helpful in the etiologic diagnosis of cryptococcal infection. The mortality rate in these 15 patients was 60% during the 2-month study. In this series, neurologic and/or psychiatric symptoms were detected in 16 (15/93)% of African patients with AIDS.     

Immunohematological reference ranges for adults from the Central African Republic

A survey was carried out on 150 healthy adults to establish hematological reference ranges for human immunodeficiency virus (HIV)-negative adults from the Central African Republic (CAR). Immunohematological mean values, medians, and 95th-percentile reference ranges were established. Mean values were as follows: leukocyte (WBC) counts, 5.28 x 10(9)/liter (males) and 5.11 x 10(9)/liter (females); erythrocyte counts, 5.20 x 10(12)/liter (males) and 4.50 x 10(12)/liter (females); hemoglobin, 15.1 g/dl (males) and 12.5 g/dl (females); hematocrit, 45% (males) and 37% (females); lymphocytes, 2,587/ micro l (males) and 2,466/ micro l (females); CD4 T cells, 927/ micro l (males) and 940/ micro l (females); CD8 T cells, 898/ micro l (males) and 716/ micro l (females); and CD4/CD8 T-cell ratio, 1.13 (males) and 1.41 (females). We concluded that (i) the WBC and hemoglobin values of healthy HIV-negative adults from the CAR are lower than the reference values currently used in the CAR and (ii) the absolute CD4 T-cell counts of healthy HIV-negative adults from the CAR are similar to values for Europeans but the absolute CD8 T-cell counts are much higher. Thus, the CD4/CD8 T-cell ratios for healthy adults from the CAR are significantly reduced compared to the ratios for healthy Europeans.     

Immunohematological Reference Ranges for Adults from the Central African Republic

A survey was carried out on 150 healthy adults to establish hematological reference ranges for human immunodeficiency virus (HIV)-negative adults from the Central African Republic (CAR). Immunohematological mean values, medians, and 95th-percentile reference ranges were established. Mean values were as follows: leukocyte (WBC) counts, 5.28 × 10⁹/liter (males) and 5.11 × 10⁹/liter (females); erythrocyte counts, 5.20 × 10¹²/liter (males) and 4.50 × 10¹²/liter (females); hemoglobin, 15.1 g/dl (males) and 12.5 g/dl (females); hematocrit, 45% (males) and 37% (females); lymphocytes, 2,587/μl (males) and 2,466/μl (females); CD4 T cells, 927/μl (males) and 940/μl (females); CD8 T cells, 898/μl (males) and 716/μl (females); and CD4/CD8 T-cell ratio, 1.13 (males) and 1.41 (females). We concluded that (i) the WBC and hemoglobin values of healthy HIV-negative adults from the CAR are lower than the reference values currently used in the CAR and (ii) the absolute CD4 T-cell counts of healthy HIV-negative adults from the CAR are similar to values for Europeans but the absolute CD8 T-cell counts are much higher. Thus, the CD4/CD8 T-cell ratios for healthy adults from the CAR are significantly reduced compared to the ratios for healthy Europeans.     

Seroprevalence of HIV-1 infections in patients consulting the clinic for sexually transmitted diseases in Bangui, Central African Republic]

140 consecutive African, exclusively heterosexual, adult outpatients to the Clinique des Maladies Sexuellement Transmissibles, with genital ulcers or urethritis, were studied in order to determine the status for HIV1-infection and syphilis. Comparison with 194 age and sex matched subjects, without STD, were chosen as controls. In the "STD"'s population, the HIV1 seroprevalence was 17.8%, and anti-treponema antibodies were found in 30% of the cases. Patients with genital ulcer were associated with a higher HIV1 seroprevalence than patients with urethritis. The "STD"'s population in Bangui is at risk for HIV1-infection (risk ratio: 2.12), and constitutes probably a very sensitive group in Central Africa for the epidemiological survey to HIV infection, and for the estimation of the prevention against AIDS.