Detection of insecticide resistance in Aedes aegypti (Diptera: Culicidae) from Cuba and Venezuela.

Four strains of Aedes aegypti (L.), one from Cuba and three from Venezuela, were bioassayed for susceptibility to eight insecticides, including the organophosphates, temephos, malathion, fenthion, pirimiphos methyl, and chlorpyrifos, and the pyrethroids, deltamethrin, lambda cyhalothrin and cypermethrin, S, S, S,-tributyl phosphorotrithioate and piperonyl butoxide were used as synergists to assess the involvement of esterases and monooxygenases in organophosphate resistance. Venezuelan strains had low levels of resistance to fenthion and malathion, and moderate to high resistance to temephos, pyrimphos methyl, and chlorpiriphos. All strains were susceptible to the pyrethroids, except the Cuban strain, which had moderate levels of resistance to cypermethrin. Organophosphate resistance in Ae. aegypti is a serious threat to control operations. Integrated strategies for Ae. aegypti control to prevent or delay pyrethroid resistance in Venezuela and Cuba are discussed.

Survival of AIDS according to injecting drug use among Puerto Rican AIDS patients.

This paper aims to: 1/ describe IDU's and non-IDU's according to age, gender, AIDS criteria and antiretroviral therapy; and 2/ assess survival differences between IDU's and non-IDU's according to age, gender, AIDS diagnosis criteria and antiretroviral therapy. This study is a survival study of a longitudinal cohort. The sample was composed of 1,258 AIDS patients of a cohort of HIV-infected adults who sought medical care at either the Immunology clinic of Bayamon or the Ramon Ruiz Arnau University Hospital between 1992 and 1999. The variables studied were: survival time of AIDS, intravenous drug use, age, gender, AIDS defining criteria and antiretroviral therapy (yes/no). The results have been that IDU's had lower survival than non-IDU's. Significant differences in the survival functions (IDU's vs non-IDU's) were found among male patients, older patients, patients with immunological criteria and patients with antiretroviral therapy. The survival among these variables was lower in IDU's than non-IDU's. This study suggested that decreased survival of IDU's may be related to later diagnosis and decreased access to drug therapy. Clinical endeavors should take into consideration the variables related to IDU's survival to develop health programs in order to enhance the quality of life and the survival of the AIDS patients.

The shape of the HIV/AIDS epidemic in Puerto Rico.

This study presents information on AIDS patients in Puerto Rico, including their general sociodemographic profile, some risk-related parameters, characteristics of vulnerable groups, and elements of the clinical spectrum of the disease. Data were analyzed from the Puerto Rico AIDS Surveillance Program and available studies about the HIV/AIDS epidemic in Puerto Rico. A total of 23,089 AIDS cases was reported to the Puerto Rico AIDS Surveillance Program from January 1981 through February 1999. The HIV/AIDS epidemic has affected mostly males and females between the ages of 30 and 49, though cases have also been reported for other age groups. The cumulative proportion of persons with AIDS who are women has increased tremendously, from 11.4% for the 1981-1986 period to 21.6% for the entire 1981-1999 period. In Puerto Rico the category of injecting drug users (IDUs) accounts for the majority of the AIDS cases (52%), followed by heterosexual contact (22%), and men who have sex with men (17%). The three main diagnoses for AIDS on the island are wasting syndrome (30.7%); esophageal, bronchial, and lung candidiasis (29.4%); and Pneumocystis carinii pneumonia (26.8%). According to 1994 vital statistics for Puerto Rico, AIDS was the fourth-leading cause of death. The overall reported AIDS mortality rate was 42.0 per 100,000 persons, with the rate for males, 67.8, much higher than it was for females, 17.4. AIDS is the first cause of death among persons between 30 and 39 years old. Intense efforts are needed to better understand the epidemic in Puerto Rico and its biology, social and family impacts, and financial costs.

Malathion resistance in Aedes aegypti and Culex quinquefasciatus after its use in Aedes aegypti control programs.

The continued widespread use of malathion in Aedes aegypti control programs in Latin America has generated insecticide resistance to this chemical in Culex quinquefasciatus but not in Ae. aegypti. To determine the extent of this resistance, the susceptibility of Cx. quinquefasciatus and Ae. aegypti from several countries to malathion was evaluated. Bioassay results indicated that all Ae. aegypti strains evaluated from Cuba, Venezuela, Costa Rica, and Jamaica were susceptible to malathion in spite of the historical use of this insecticide in Ae. aegypti control programs in these countries. In contrast, a high level of resistance to this insecticide was found in Cx. quinquefasciatus from Venezuela, Colombia, Brazil, and Cuba. Synergist assays indicated that neither esterases nor mixed-function oxidases (MFOs) were involved as the resistance mechanism to malathion in any of the Ae. aegypti strains tested. In Cx. quinquefasciatus, synergist assays confirmed that esterases played an important role in malathion resistance but MFOs were not involved in causing malathion resistance in this species. Biochemical assays showed that both resistance mechanisms were present in the Ae. aegypti and Cx. quinquefasciatus populations. Acrylamide electrophoresis gels revealed that all Ae. aegypti strains had a strongly staining, clear band, named A4, and had a relative mobility (Rm) value of 0.7. Analysis if the results of this study suggested that malathion could continue to be used for the emergency control of Ae. aegypti, the mosquito vector for dengue and dengue hemorrhagic fever in the Americas, but that malathion is probably not effective for the control of adult Cx. quinquefasciatus in urban areas. Therefore, control operations should integrate nonorganophosphate insecticides such as pyrethroids for control of these 2 species found in the urban environment.

Psychological and behavioral issues of a cohort of Puerto Rican HIV/AIDS patients.

UNLABELLED: The current study describes the psychological and behavioral issues of a cohort of Puerto Rican HIV/AIDS patients. Differences in the depression mean score were determined and the predictor variables of depression among a cohort of Puerto Rican HIV/AIDS patients were also identified. DESIGN: Cross-sectional survey of a longitudinal cohort (N=1,500). METHODS: The setting of this study was the Immunologic Clinic and the Dr. Ramón Ruiz Arnau University Hospital in Bayamón, Puerto Rico. The sample was composed initially of 58 patients who had completed the Beck Inventory depression test (alpha Cronbach=0.93) and who were registered at the HIV/AIDS Central Registry between April 1995 and July 1996. RESULTS: Women had higher depression scores than men. High education groups (>12th grade) had lower depression scores than low education groups. Patients reporting heterosexual practices had higher depression score than patients without that practice. A multiple linear regression showed that predictors variables of the depression score were gender and education. CONCLUSIONS: A wide spectrum of psychological and behavioral features were present within the HIV/AIDS sample, including depression.

Psycho social and clinical spectrum of HIV/AIDS injecting drug users in Bayamón, Puerto Rico.

OBJECTIVES: To describe the demographic characteristics, the risk related practices, and the clinical and immunological features of Puerto Rican HIV injecting drug users (IDU's). DESIGN: Cross-sectional survey of a longitudinal cohort (N=1,500). METHODS: The HIV Central Registry at the Universidad Central del Caribe has been recruiting HIV/AIDS patients attending the Immunologic Clinic and the University Hospital Ramón Ruiz Arnau since may 1992. 1500 patients have been interviewed and a record including demographic, risk related, clinical and immunologic data has been created for each one of them. Chi square and t-tests were performed to assess the potential significant differences of the TDU's vs the non-IDU's. RESULTS: 57.1% of the HIV/AIDS patients were IDU's. Most of them were males, had a lower education level, with an age fluctuating between 27 to 36 years old and most of them were unemployed. Most IDU's reported to have had heterosexual relations. With regard to the clinical spectrum, Pneumocystis carinii pneumonia (PCP) was the only indicative condition associated with injecting drug use (IDU), as well as bacterial endocarditis, chronic diarrhea, night sweats and idiopathic fever. The spectrum of vulnerabilities of IDU's is larger than that of non-IDU's, with regard to psycho-social, behavioral and clinical features. These vulnerabilities can limit their access to services and render their compliance to treatment more difficult.