Dried blood spots versus plasma for the quantification of HIV-1 RNA using the manual (PCR-ELISA) amplicor monitor HIV-1 version 1.5 assay in Yaounde, Cameroon.

OBJECTIVES: Considering the recent accrued need for viral load quantification in resource-limited settings, this study evaluated the use of dried blood spots (DBS) compared to plasma as a means of sample collection and storage for HIV-1 RNA quantification using a non-automated assay. METHODS: Venous blood was collected from 60 consenting HIV-1-positive patients, plasma separated within 4 hours, and stored at -20 degrees C. Venous blood, 50 microL, was blotted on 4 designated areas of Whatman filter paper and air-dried at room temperature for 2 hours. RESULTS: There was a strong statistically significant correlation between HIV-1 RNA viral load using plasma and DBS (r = .955, P < .001). On average plasma viral loads were only slightly higher than DBS viral loads (mean difference: 0.06 log(10) copies/mL). CONCLUSION: Even when using an entirely manual HIV-quantification assay, DBS may provide a reliable, cost-effective method for sample collection and storage for HIV-1 RNA quantification in resource-limited settings.

The Potentials of Fas Receptors and Ligands in Monitoring HIV-1 Disease in Children in Yaoundé, Cameroon.

OBJECTIVE: Difficulties in systematically monitoring HIV viral load in resource-limited settings prompt the search for alternate approaches. The authors aimed at assessing the correlation between the plasma levels of soluble forms of Fas receptors (Fas) and Fas ligands (FasL) with standard indicators of HIV disease progression in children. METHODS: Twenty-two HIV-1-positive children were enrolled in Yaounde. CD4 counts, CD4% counts, plasma levels of Fas, FasL, and HIV-1 RNA levels were assayed. RESULTS: The correlation coefficients (P values) between FasL levels and each of HIV-1 viral load, CD4 counts, and CD4% were, respectively, .56 (.01), -.29 (.18), and .30 (.18). On the other hand, the respective correlation coefficients (P values) with Fas levels were .12 (.60), -.30 (.18), and -.29 (.19). CONCLUSION: The significant correlation between levels of HIV-1 viral load and FasL suggests that the latter needs to be further studied as a potential biomarker to monitor HIV-1 disease progression in children in resource-limited setting.

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.

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.

Immunological cross-reactivities among three herpesviruses.

Sixty adults were tested for humoral and cell-mediated immunity to varicella zoster virus (VZV), type 1 herpes simplex virus (HSV-1) and the human cytomegalovirus (CMV). Since herpesviruses share common antigens, we compared results in these individuals to assess whether our tests gave false positives due to cross-reactions. Of the 60, IgG antibody to VZV, HSV-1, CMV tested by ELISA was detected in 51 (85%), 34 (57%) and 20 (33%) respectively. All possible permutations of results were obtained and there was no evidence of cross-reactivity among the viruses. Lymphocyte transformation performed in 20 was found to be positive in 16 (80%), 13 (65%) and 8 (40%) for VZV, HSV-1 and CMV respectively. Similarly, all possible permutations of results were obtained. In addition, 8 subjects were found to have positive lymphocyte transformation responses for one or other of the viral antigens but no specific antibody was found in their sera. Thus, the antibody and lymphocyte transformation test were not influenced by possible cross-reacting antigens among the 3 herpesviruses we studied. Both tests are necessary to firmly establish whether a subject has had a prior infection.

Generation of phenotypically different T cell populations by cell-free or cell-bound preparations of varicella zoster virus.

We used three different preparations of varicella zoster virus (VZV) to sensitise mononuclear cells obtained from VZV immune donors. These were autologous infected fibroblasts, live cell free virus and heat inactivated cell free virus. After 14 days of in vitro sensitisation and expansion with interleukin-2, the mononuclear cells which had been exposed to autologous infected fibroblasts had generated mainly cells of the cytotoxic/suppressor phenotype (CD8) while those stimulated with cell free virus (live or heat inactivated) had generated cells of the helper/inducer phenotype (CD4). Functional assays showed that the effector cells generated after exposure to autologous infected fibroblasts lysed autologous virus infected target cells but not uninfected cells. Effector cells generated in the same way but lacking HLA identity with the virus infected target cells failed to demonstrate cytotoxicity. None of these effector cells showed any significant natural killer cell activity. No specific cytotoxicity was obtained by effector cells generated after exposure to cell-free virus. We conclude that the way in which VZV antigen is presented to the mononuclear cells influences the cell type responding in tissue culture. These findings would be useful in the generation of T cell clones of different cell surface phenotype and function.

Hepatitis D in Yaounde, Cameroon.

Although 10% of the Yaounde population are hepatitis B surface antigen (HBsAg) positive, nothing is known about hepatitis D virus (HDV) infection in them. Sera from 110 HBsAg subjects were tested for HDV infection (antibody and antigen). The subjects were 43 pregnant women, 23 prostitutes, 20 patients with febrile jaundice, 16 multitransfused sickle cell children and 8 medical students. Thirty of the 110 (27.3%) had antibodies to the HDV (HDV-Ab). Two of 91 tested for HDV antigen (2.2%) were positive. The highest HDV-Ab prevalence (62.5%) was obtained from sickle cell children (10/16). Thus, HDV infection was found in about one fifth to one third of the HBsAg-positive subjects we studied and the main route of transmission appears to be by blood transfusion.

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.

Immunity to varicella-zoster virus in a normal adult population.

Sera from 489 trainee nurses were examined, by the ELISA technique, for the presence of varicella-zoster virus specific antibody; antibody was found in 446 (91.2%). In more detailed investigations of specific immunity in 33 healthy adults with a past history of chickenpox, 32 (97%) showed a positive lymphocyte transformation test, but only 11 out of 23 examined (48%) demonstrated mononuclear cell production of specific antibody in vitro; serum antibody was found in 30 (91%) by the ELISA and in 25 out of 26 examined (96%) by the FAMA technique. A high degree of correlation was found between both a positive lymphocyte transformation and the presence of serum antibody and a past history of chickenpox.

[Cysticercosis and epilepsy: a case-control study in Mbam Valley, Cameroon]. / Cysticercose et épilepsie: étude cas-témoins dans la Vallée du Mbam, Cameroun.

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.

Afriflu--international conference on influenza disease burden in Africa, 1-2 June 2010, Marrakech, Morocco.

The burden of influenza disease is to a large extent unknown for the African continent. Moreover, the interaction of influenza with common infectious diseases in Africa remains poorly described. Solid scientific evidence on the influenza disease burden in Africa is critical for the development of effective influenza vaccine policies. On 1st and 2nd June 2010 in Marrakech, Morocco, over eighty surveillance and influenza experts from 22 African countries as well as Europe and America met at the 'Afriflu' conference to discuss influenza challenges and solutions for the continent. During the meeting, participants exchanged their experiences and discussed a wide variety of topics related to influenza in Africa, including diagnosis, surveillance, epidemiology, and interventions. The meeting concluded with a pledge to improve influenza knowledge and awareness in Africa, with an emphasis on accurate determination of disease burden to help orient public health policies.

Curative and preventive treatment of uncomplicated malaria in public health institutions in Cameroon.

Chloroquine-resistant Plasmodium strains are found in certain foci in Cameroon. We do not know what contribution drug prescriptions and drug pressure had in bringing this about. We contacted 66 persons (39 doctors and 27 nurses) who prescribe antimalarial drugs in Cameroon regarding their prescription habits; 46 (69.7%) responded. The three most prescribed drugs for uncomplicated malaria were quinine (84.4%), chloroquine (80.4%) and amodiaquine (80.4%). The most common reason for prescribing the drugs was availability. The drug of choice for the treatment of uncomplicated malaria was chloroquine with amodiaquine and quinine being second best for doctors and nurses, respectively. The form of treatment preferred by most doctors (ie 46%) was tablets while most nurses (42%) preferred injections. Prophylatic antimalarials were prescribed by 73% of the doctors and by 83% of the nurses. Doctors prescribed mainly to children and pregnant women while nurses prescribed to everyone. The drugs used were chloroquine, amodiaquine, quinine and pyrimethamine. Ten doctors and four nurses had encountered at least one case of drug resistant malaria. The most common evidence on which the diagnosis had been based was the absence of improvement on the treatment prescribed. The implicated drugs were chloroquine, amodiaquine and quinine. There was evidence of major differences in the practice of the respondents regarding treatment, prophylaxis and the diagnosis of drug resistance. These results indicate an urgent need for a national antimalarial drug policy in Cameroon.

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.