Genetic subtypes of HIV-1 in the Philippines

OBJECTIVES

To determine the genetic variability of HIV-1 amongst infected Filipinos and to analyze phylogenetic relationships, temporal introductions and transmission dynamics of identified variants.

METHODS

Polymerase chain reaction amplification and direct sequencing of a 204 base-pair fragment of the env C2-V3 region from uncultured peripheral blood mononuclear cells obtained from 51 HIV-1-positive Filipinos infected from 1987 to mid-1996. Evolutionary distance and phylogenetic relationships among the DNA sequences were estimated.

RESULTS

The 51 Philippine strains were classified into five env V3 subtypes, namely subtype B (n = 37), subtype E (n = 8), subtype A (n = 3), subtype C (n = 2) and subtype D (n = 1). The overall env nucleotide divergence ranged from 11.7 to 32.2%. The nucleotide variation appeared to be random and no temporal ordering was observed. The variation of the sequences at the tip of the V3 loop was very broad. Subtypes B and C isolates did not show close genetic relationship to other Asian variants. Only three of the subtype E strains had close affinity to known Asian sequences. The majority (94%) of the subjects acquired the infection by sexual transmission. About two-thirds were presumably infected outside the Philippines, whereas the remaining were infected indigenously. Information was limited to allow segregation of the identified subtypes by mode of transmission or risk groups.

CONCLUSION

Our findings demonstrate the presence of multiple genetic subtypes of HIV-1 in the Philippines. The apparent geographic range of previously reported genotypes in South and South-east Asia was extended and has obvious implications for env-based antiviral interventions.

Results of a model AIDS prevention program for high school students in the Philippines

OBJECTIVES

To describe the sexual practices of high school students; to describe the process of development of a school-based AIDS prevention program; and to evaluate the effect of this program on students' AIDS-related knowledge, attitudes and AIDS-preventive behaviors.

SUBJECTS AND METHODS

A cluster-randomized, controlled trial with pretest/post-test evaluation was conducted in four demographically similar public high schools in a semi-urban district of Metro Manila, the Philippines. Of 845 high school students who participated in the baseline survey, 804 (95%) completed a postintervention questionnaire.

INTERVENTION

An AIDS prevention program was developed by public high school teachers together with local AIDS experts, social scientists and health educators. The teacher-led AIDS program was designed to provide students with accurate information about AIDS, particularly in dispelling misconceptions about casual contagion, to foster positive attitudes towards people with AIDS and to develop skills aimed at clarifying values and assessing intended behavior.

RESULTS

At baseline, 11% of students (20% of males and 4% of females) reported ever having had sexual intercourse (mean age 14 years). Among these, condom use was low (24%). After implementation of the AIDS prevention program, statistically significant effects favoring the intervention group were observed in knowledge and attitudes towards people with AIDS. While there was no statistically significant overall effect on intended preventive behavior, the program appeared to delay the students' intended onset of sexual activity.

CONCLUSIONS

A sizable number of Filipino high school students are sexually active but condom use is low. School-based AIDS prevention programs can be developed and implemented in developing countries with the assistance of school personnel to address sexual issues. Our program was successful in increasing AIDS-related knowledge and improving attitudes towards people with AIDS. Supplementation with other preventive activities may be needed to achieve lasting changes in students' risk-taking behavior.

HIV-1 variants in South and South-East Asia

HIV spread in South and South-East Asia is most alarming, and genetic variability of HIV-1 is an important consideration in vaccine development. In this study, we examined the third variable (V3) region of env gene of HIV-1 variants prevalent in Thailand, Malaysia, India, and the Philippines. By phylogenetic tree analyses, an HIV-1 variant from an injecting drug user (IDU) in Thailand belonged to subtype B, and HIV-1 variants from 2 IDUs in Malaysia were classified into 2 subtypes, B and E. One HIV-1 variant from a male homosexual in the Philippines belonged to subtype B. Out of 8 HIV-1 variants from sexually transmitted disease patients in India, 7 belonged to subtype C, and one to subtype A. Although the total number of individuals examined in this study was limited, 4 HIV-1 subtypes were found in South and South-East Asia and large international movements of HIV-1-infected individuals in this region could induce global dissemination of these HIV-1 variants.

AIDS education for hospital workers in Manila: effects on knowledge, attitudes, and infection control practices

OBJECTIVE

To evaluate an AIDS education intervention for health workers in Metro Manila hospitals.

METHODS

A randomized controlled education program consisting of lectures, role-plays, posters and pamphlets was delivered to physicians, nurses, laboratory technologists and orderlies in Manila hospitals. Knowledge, attitudes and infection control practices were measured before, immediately after, and 2 months after the intervention.

RESULTS

Baseline survey among 641 hospital workers revealed poor knowledge, negative attitudes towards AIDS patients, and inappropriate infection control practices. Immediately after the intervention, there was significant improvement in (1) knowledge scores (8.7-11.2 in the intervention group versus 8.5-9.5 in the control group; range, 0-14), (2) attitude scores (54.4-60.6 versus 54.6-56.8; range, 22-88), and (3) needle-recapping practices (14-43% versus 39-43%) (all P values < 0.001). After 2 months, attitude scores in the experimental group fell to the same level as those of the control group, while improvements in knowledge and needle recapping were largely maintained. Role-playing was considered by the participants to be the most effective component of the intervention.

CONCLUSIONS

These results suggest that AIDS training for hospital workers in the Philippines and in similar countries is necessary and can be effective. Ideally, such training should include role-playing and should be ongoing in order to sustain the effect.

Relevance of antibody content and test format in HIV testing of pooled sera

OBJECTIVE

To determine the effects of HIV-1 antibody level and test-format characteristics on testing pooled sera.

DESIGN

This study was designed with a laboratory exercise followed by test observations on serosurveillance samples.

METHODS

Sera with low, medium and high (n = 22, 12 and 20, respectively) antibody titers were pooled with HIV-1-negative sera and tested with two enzyme-linked immunosorbent assays (ELISA) and a particle agglutination test. The same kits were used to test single and pooled (batches of five, 10 and 20) samples collected from 3000 blood donors and sex workers. These samples were then seeded with 50 varying antibody-containing sera and similarly tested. Initial reactivities, sensitivities, and specificities for all test kits were calculated and compared.

RESULTS

In the laboratory exercise, all reactive pools of five were detected. False-negative pools in batches of 10 and 20 with low antibody titers were noted with one or both ELISA, but not with the particle agglutination method. Testing 3000 samples revealed three confirmed reactive samples and 100% sensitivity/specificity for all kits, for both single and pooled sera testing. Increased initial reactivity (IR) was noted for the two ELISA. Examinations of pools of the seeded 3000 samples with the two ELISA showed false-negative reactivity with pools of 10 and 20 when pools contained low antibody sera (sensitivities and specificities of 92-97.9% and 98.1-100%, respectively). Again, increased IR was seen with the ELISA. False-negative pool and increased IR was not seen with the agglutination test (sensitivity/specificity 100%).

CONCLUSIONS

We recommend the use of the particle agglutination assay for testing pooled sera of batches of 20 or less. Components of reactive pools should then be tested and reactive samples should undergo supplementary testing. Pooled samples tested by ELISA should not exceed five per batch. Retesting of reactive pools, testing of its components, and supplemental test(s) of reactive sera should then follow. The optimum pool size for most laboratories is five, with the best technical and economic performance seen with the particle agglutination assay.

Prevalent serogroups and antimicrobial susceptibility of Shigella strains in Metro Manila, 1982-1988

From 1982 to 1988, Shigella was detected in 4% of stool specimens cultured at The Research Institute for Tropical Medicine (RITM), Manila. S. flexneri was the most prevalent serogroup with 2a, 1b and 1a as the predominant serotypes. Isolation was most frequent during the July to December period. Drug resistance was most often observed in S. flexneri with serotype 2a exhibiting resistance to the combination of ampicillin, chloramphenicol, tetracycline and streptomycin. More multiple-drug than single-drug resistant strains were observed for the last four years. Ampicillin is still the most frequently used drug for most forms of shigellosis in the Philippines. However, the demonstration of increasing resistance among the isolates studied in RITM underscores the need to monitor antibiotic susceptibility studies and document the emergence of resistant strains in the entire country.

Emerging patterns of HIV infection and control in the Philippines

A total of 50 carriers of the human immunodeficiency virus (HIV), 46 of them female prostitutes, have been detected through seroprevalence surveys by the Department of Health, Manila. Infection rates are highest in two small cities near foreign military bases and in the tourist district of MetroManila. Nine patients with the acquired immunodeficiency syndrome (AIDS) who contracted the disease outside the country have been reported, with opportunistic infections being the major clinical feature. Public information measures heavily utilize the mass media, and there is anecdotal evidence that awareness of the disease among the urban population is increasing. The National AIDS Committee foresees that a large proportion of the cases seen in the Philippines over the next few years will be returning nationals who were infected abroad.