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Biomedical subjects

P M Ndumbe

Publications and source records attributed to P M Ndumbe.

At least 19 recordsLinked to original sources

Interactions between human immunodeficiency virus and herpes viruses within the oral mucosa.

There is evidence from clinical case reports and epidemiological studies that human immunodeficiency virus (HIV) can be transmitted through oral sex. Herpes viruses that appear in the oral mucosa might influence the oral replication of HIV. A review of data suggesting that interactions occur between HIV and herpes viruses indicates that such interactions might operate in the oral mucosa. Defining the mechanisms by which herpes viruses interact with HIV in the oral mucosa should permit intervention measures to be targeted more precisely.

CD4 Antigens↗

[Cysticercosis and epilepsy: a case-control study in Mbam Valley, Cameroon].

The impact of neurocysticercosis in Africa is not well known, and its role in the occurrence of epilepsy is not well defined. The concomitant high prevalence of both diseases in this region suggests a causal association of cysticercosis and epilepsy. The few attempts to find such a link in Africa have yielded discordant data. In order to answer this question, we conducted a case-control study between June and August 1998 in the Bilomo village in Central Cameroon, where a recent study had demonstrated very high epilepsy prevalence of 58/1000. Ninety-three epilepsy patients and eighty-one age matched controls were included. All subjects were examined by a neurologist and serology for cysticercosis was performed using an ELISA method. Serologies for cysticercosis were positive in twenty-nine out of one hundred and seventy four patients (16.7%; 95% CI: 11.6-23.2). Seventeen cases (18.3%) and twelve controls (14.8%) had a positive serology The odd ratio was 1.3 (95% CI: 0.6-3.0). This study was not in favour of an epidemiological relationship between cysticercosis infection and epileptic disorders.

Adolescent↗

Serological findings amongst first-time blood donors in Yaoundé, Cameroon: is safe donation a reality or a myth?

Blood safety remains an issue of major concern in transfusion medicine in developing countries where national blood transfusion services and policies, appropriate infrastructure, trained personnel and financial resources are lacking. This is aggravated by the predominance of family and replacement, rather than regular benevolent, nonremunerated donors. Thus, in order to identify and encourage healthy, regular and benevolent nonremunerated donors, consenting first-time blood donors in the Yaoundé University Teaching Hospital were screened for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBSAg), hepatitis C virus (HCV), human T-cell lymphotropic virus-I (HTLV-I) and syphilis using standard methods. Of 252 first-time donors recruited, 66 (26.2%) were positive for at least one of the infections screened. There were 7.9% positive for HIV, 10.7% for HBSAg, 4.8% for HCV and 9.1 and 1.6%, respectively, for syphilis and HTLV-I. About 30% of the 66 infected persons had co-infections. HIV-positive donors had a significantly increased risk of being positive for antibodies to syphilis (OR = 7.27; 95% CI = 2.23-23.51; P = 0.0007), not observed for HBV, HCV and HTLV-I. These results suggest that blood transfusion is still very unsafe in this community and that it is imperative that emphasis be laid on donor education. Furthermore, donors with a history of sexually transmitted infections should be totally excluded from all donations.

Adolescent↗

Biological phenotypes of HIV-1 subtypes A and B strains of diverse origins.

The identification of specific biologic phenotypic traits that can be correlated with different HIV-1 genetic subtypes was sought. The genetic subtypes were determined by either sequencing (Cameroonian strains, n = 18) or by the heteroduplex mobility assay (HMA) (Belgian strains, n = 21 and Ivorian strains, n = 25). Seventeen (81%) of the 21 Belgian isolates belonged to subtype B and 4 (17%) were subtype A strains. Subtype A variants were predominant in the two African countries studied; 11 (61%) of 18 strains from Cameroon and 23 (92%) of 25 strains from the Ivory Coast. Of the 64 isolates, 38 (58%) and 19 (29%) belonged to subtypes A and B, respectively. No significant difference was observed for biological phenotypes (slow/low and rapid/high) of both genetic subtypes. In symptomatic individuals, however, a significantly higher number of subtype B isolates were of rapid/high phenotype, compared with subtype A (5 of 10; 50%) vs. 2 of 22; 9%), respectively; X2 = 6.7, P = 0.02). The findings suggest that overall HIV-1 isolates belonging to genetic subtype B are not distinguishable from subtype A variants on the basis of their biological phenotypes. Syncytium-inducing variants were less prevalent regardless of the geographic origin of the isolates.

Base Sequence↗

Comparison of Edmonston-Zagreb, Connaught and Schwarz measles vaccines in Cameroonian infants aged 3-8 months.

Eighty-five Cameroonian infants aged between 3 and 8 months were vaccinated with a high-dose Edmonston-Zagreb (EZ) strain (10(5.6) TDIC50), 81 with a low-dose Connaught strain (10(3) TCID50) and 74 with a medium-dose Schwarz strain (10(4) TCID50). Side-effects were mild (less than 32% of infants) and were not significantly different among the groups, nor were postvaccination anti-measles antibody levels. Postvaccination seropositivity and seroconversion rates were respectively 91.6% and 69% for EZ, 85.3% and 67.7% for Connaught and 75.6% and 62.2% for Schwarz. In the light of concerns regarding high-titre measles vaccines, the overall performance of the Connaught strain warrants its wider evaluation in young infants.

Antibodies, Viral↗

Genotypic subtypes of HIV-1 in Cameroon.

OBJECTIVE: The only two HIV-1 strains (ANT70 and MVP5180) reported to date from Cameroon are members of the outlier clade (group O). In this study, we assessed the prevalence of group O viruses and other HIV-1 subtypes in Cameroon. DESIGN: A phylogenetic analysis of 18 HIV-1 strains isolated from seropositive individuals from Yaoundé and Douala, Cameroon. METHODS: A 900 base-pair fragment of the env gene coding for V3, V4, V5, and the beginning of gp41 of 17 out of 18 HIV-1 isolates from Cameroon was amplified, cloned and sequenced using polymerase chain reaction. A phylogenetic tree was constructed. RESULTS: The overall env nucleotide sequence divergence among the Cameroon isolates ranged from 6.1 to 27.5%. In a phylogenetic tree, six subtypes were identified when compared with 23 reference strains of different geographic origin. Of these 17 Cameroonian strains, 11 (61%) were of subtype A of which the interpatient distances at the sequence level varied from 6.1% to 18.3% (average, 11.9%). Three (17%) strains were of subtype F, and the other three strains (6% each) belonged to subtypes B, E and H, respectively. The remaining isolate was classified as belonging to group O, on the basis of the sequence of part of the pol gene. A very broad spectrum of different tetrameric amino-acid sequences was observed at the apex of the V3 loop. Eleven strains contained the tetrameric globally predominant GPGQ sequence at the tip of the V3 motif. Two strains had the GPGR sequence typical of the American and European HIV-1 strains. The remaining tetrameric sequences included GPGS, GSGQ, GRGQ, and GLGR. CONCLUSION: These findings on a limited number of viruses suggest extensive env gene diversity of HIV-1 strains from Cameroon, and could have implications for vaccine development in Africa.

Amino Acid Sequence↗

Seroprevalence of hepatitis and HIV infection among rural pregnant women in Cameroon.

Since some hepatitis viruses and the human immunodeficiency viruses share common modes of transmission, such as the sexual route, we undertook to investigate the prevalence of antibodies to these and other pathogens among 384 rural pregnant women. Our study was intended to form the basis of infection management policies in pregnancy. Antibodies and other markers of the hepatitis A, B, C, and D viruses (HAV, HBV, HCV, HDV), the human immunodeficiency virus type 1 (HIV-1) and Treponema pallidum were sought. We tested for antibodies to the viruses using the appropriate enzyme-linked immunosorbent assays. HCV and HIV-1 infection were confirmed using standard immunoblotting techniques. Regarding HBV, we tested for the surface antigen (HBsAg), antibody to the surface antigen (anti-HBs) and antibody to the core antigen (anti-HBc). A non-specific test, the rapid plasma reagin test (RPR), was used for estimating Treponema pallidum (syphilis) infection. We found an overall prevalence of antibodies to HAV of 91.4%, to HCV of 6.8%, to HDV of 0%, and to HIV-1 of 3.5%. We found no IgM antibodies to HAV. The incidence of HBV markers was as follows: 5.4% for HBsAg, 61.3% for anti-HBs, and 84.6% for anti-HBc. RPR reactivity was found in 15.8% of the women. These results will be used to establish appropriate management and preventative policies for women attending the antenatal clinic. Prevention and appropriate early treatment of infections in these women will be considered.

Adolescent↗

Infections among pygmies in the Eastern Province of Cameroon.

The health requirements of pygmies is poorly understood because of their continued isolation from the other tribes in Central Africa. This study was undertaken among the Baka pygmies of the Eastern Province of Cameroon to generate basic health data among them. A total of 141 adults (18-45 years) were tested for the hepatitis B surface antigen (HBsAg), antibody to the surface antigen (anti-HBs), antibody to the core antigen (anti-HBc) and antibody to the hepatitis C virus (anti-HCV). All HBsAg-positive sera were tested for the hepatitis B e antigen (HBeAg) and antibody (anti-HBe). The presence of antibodies to the hepatitis D virus was determined in most of the anti-Hbs-positive sera, and some of the HBsAg-positive sera. In addition to these, previous infection with syphilis, measles, HIV 1/2 and HTLV were determined by looking for the specific antibodies. We found HBsAg in 14.2% (20/141), anti-HBs in 93.6% (132/141), anti-HBs in 52.2% (73/140), anti-HCV in 7.9% (11/139, measles antibody in 99.3% (139/140), antibody to Treponema pallidum in 13.4% (18/134), antibody to HTLV-1 in 10.9% (15/138) and antibody to HIV-1 in 0.7% (1/140) of the sera tested.

Adolescent↗

Hepatitis C virus infection in different populations in Cameroon.

We tested serum samples collected in an urban setting (Yaounde) and in a rural area (Manyemen) for the presence of antibody to hepatitis C virus (HCV) (anti-HCV). Screening was done by second-generation ELISA and confirmation with second-generation RIBA. In Yaounde, anti-HCV was found in 12.5% of patients with febrile jaundice (95% CL 3.8-21.2), 5.5% of pregnant women (95% CL 3.3-7.3), 0% of children below 4 years of age, 31% of sickle cell patients (95% CL 20.2-41.8%), 1.6% of medical students (95% CL 0-4.7%) and 15.4% of prostitutes (95% CL 8.5-22.3). Only HBsAg-negative sera were tested for anti-HCV, except sera originating from subjects with febrile jaundice. In Manyemen, anti-HCV was detected in 6.4% of blood donors, 6.0% of pregnant women, 5.3% of HIV-positive subjects, 7.3% of RPR-positive and 3.9% of RPR-negative subjects. There was an increase in antibody prevalence with age. We conclude that HCV infection is common in Cameroon and that it is transmitted mainly by blood transfusion and probably by sexual activity.

Adolescent↗

Characteristics of HIV/AIDS patients attending a rural hospital in Cameroon. Manyemen HIV/AIDS Team.

Manyemen, a rural community in Cameroon, has now been hit by the HIV epidemic. This paper describes the experiences gained at the Presbyterian General Hospital in Manyemen between 1990 and 1992 regarding HIV infection in pregnant women, AIDS case management, counseling and home visits. A total of 383 pregnant women attending antenatal clinics were tested. We found a 2.9% HIV-1 seroprevalence and a 17% reactivity to a non-specific syphilis test, rapid plasma reagin, RPR. In 1990, 1991 and 1992, we diagnosed 55, 89 and 94 cases of clinical AIDS respectively. New TB cases seen in the same period showed the following HIV positive rates 3.5%, 2.4% and 5.8%. A detailed study of 78 AIDS patients revealed that the five most common presenting signs in our patients were wasting (80%), prolonged fever (28%), chronic diarrhoea (17%), oropharyngeal candidiasis (14%) and pulmonary TB (10%). Pretest and post test counseling is routinely done by the AIDS team. About 79% of the patients were post counselled as were 27% of their relatives. Home visits have been started. These results show that AIDS is no longer an issue confined to cities in Cameroon and that rural hospitals should institute a programme, similar to ours, to help them cope with the AIDS epidemic.

Acquired Immunodeficiency Syndrome↗

Prevalence of infections affecting the child among pregnant women in Yaounde, Cameroon.

The prevalence of infections which have deleterious effects to either the mother or the fetus during pregnancy are unknown in Cameroon. To formulate appropriate antenatal screening policies for the Central Mother and Child Clinic in Yaounde, we tested random sera obtained from 1,014 stored samples previously obtained from pregnant women. One hundred and fifty sera were tested for the presence of the hepatitis B surface antigen (HBsAg), 544 for syphilis antibodies, 192 for antibodies to rubella and 192 for antibodies to Toxoplasma gondii. We found the HBsAg in 25.3% (38/150) of the subjects, antibodies against syphilis in 15.9% (87/544), antibodies to the rubella virus in 83.9% (161/192) and evidence of toxoplasma infection in 77.1% (148/192). Of the 38 HBsAg-positive subjects, 5.2% and 55.3% were positive for the HBe antigen and HBe antibody, respectively. We found a high prevalence for these infections in the antenatal clinical attendants. The data will be used to develop an appropriate control strategy for them.

Animals↗

Retrovirus infections in the south of Cameroon.

The results of a national HIV seroprevalence survey carried out in 1986/87 showed a 1% HIV seroprevalence in the South of Cameroon, which is higher than in the other regions of the country. We here demonstrate the presence of HTLV-I infections in the South of Cameroon with possible clustering of infection in some villages. Some evidence suggestive of the presence of HTLV-II was obtained. Sera from patients with onchocerciasis did not react on HTLV testing. No HTLV associated haematological or neurological syndromes were observed during this survey. Regarding the human immunodeficiency viruses, the HIV-1 prevalence varied from 0 to 3% in the different populations studied. None of the subjects was HIV-2 positive.

Blotting, Western↗