- Email: [email protected]
Anti-tuberculosis drug resistance in an HIV epidemic province, Thailand
20S
INFECTIOUS DISEASE
HIV INCIDENCE RATES AMONG DRUG USERS IN AN HIV EPICENTER IN NORTHERN THAI, LAND, 1 9 8 9 - 1 9 9 7 . P. Sawanpanyalert, S. Supawitkul, H. Yanai, P. Saksoong, S. Piyaworawong. Field Epidemiology T r a i n i n g Program, Ministry o f Public Health, Thailand; Mae C h a n Hospital, C h i a n g Rai, Thailand; Research Institute of Tuberculosis, Tokyo, Japan. Objective: To determine trends and associated risk factors of HIV incidence (1989-1997) in a drug abuse treatment clinic in northern Thailand where HIV is epidemic. Design: Retrospective cohort study of drug users who were initially HIVnegative and treated more than once. Nine years (1989-1997) of data (excluding names) from logbook were transcribed and double entered into two separate computer files and validated. For each patient, the dates of the first HIV-negative test, the last HIV-negative test, and the first HIVpositive tests were determined. Setting: Drug abuse treatment clinic at district level hospital. Participants: 378 repeat drug users who meet the criteria above in 19891997. Interventions: None. Main Outcome Measure(s): HIV incidence rate per 100 person-years of observation (PYO). HIV seroconversum was assumed to follow a uniform distribution between last negative and first positive HIV test. The 95% confidence interwll (C1) for the incidence was calculated using Poisson approximation method. Results: Of 378 repeat patients 16 (4.2%) converted to HIV positivity. This is equiw~lent to 5.1 per 100 PYO (95% CI = kl-8.4). The incidence remained relatively stable over the study period while the prevalence was on the decline. The younger (-<30 years old) had a higher incidence (10.7 per 100 PYO) than the older (2.7 per 100 PYO). The incidence was higher among Thai lowlanders (5.8 per 100 PYO) than other ethnic minorities (1.8 per 100 PYO). Drug injectors (8.0 per 100 PYO) had a higher incidence than drug smokers (2.6 per 100 PYO). Conclusions: Prevalence can give illusional results. It is necessary to know baseline HIV incidence to monitor and ew~luate an HIV intervention program,
IMMUNITY
FOR
YELLOW
FEVER
VIRUS
(YFV)
AS A RISK F A C T O R FOR D E N G U E HEMORR H A G I C F E V E R ( D H F ) . Luis Villar. C E U , Universidad Industrial de Santander, Bucaramanga, Colombia. O b j e c t i v e : To determine if patients with DHF are more predisposed to have immunity fi)r YFV than those with (Non-hemorrhagic) Dengue Classical Fever (DCF), since YF vaccine produces an immune response similar to a primary dengue infection and pathogenesis of DHF implicates consecutive infections by dengue virus. Design: Case-control study. Setting: The General Community Hospital at Bucaramanga, a general tertiary level referral center for the Santander province. Participants: Patients with acute dengue virus infection. 120 cases of DHF by World Health Organization criteria and 120 control patients who experienced the classical form of the illness. Interventions: A Neutralizing Antibody Test (NAT) for YFV immunity status. The primary or secondary dengue virus infection was defined through a haemagluttination inhibition test; clinical chart was reviewed to obtain information about clinical condition, confounding and risk factors. M a i n Outcome Measure(s): YFV immunity status. Results: The association among immunity for YFV and DHF was contemplated in a logistic regression model, as well as other important variables such as age, sex and kind of infection (primary or secondary infection). There was no relationship between YFV immunity and DHF (OR = 0.988; CI 95%: 0.996-1.006). The risk of having antibodies against YFV was higher in older than 15 years (OR = 2.572; CI 95%: 1.396-4.737), while living in the urban area was a protecting factor for YFV immunity (OR = 0.313;.CI 95%: 0.158-0.621). Conclusions: YFV immunity is not a risk factor for developing DHF in patients with acute infection by dengue virus.
ANTI-TUBERCULOSIS AN HIV EPIDEMIC
DRUG RESISTANCE PROVINCE, THAILAND.
IN' H.
Yanai, S. Supawitkul, N. Kunyanone, T. Yoshiyama, D. Rienthong, P. Akarasewi. International Epidemiologic Association, C h i a n g Rai Hospital, Thailand; Research Institute of Tuberculosis, Tokyo, Japan; TB division, M O P H , Bangkok, Thailand. O b j e c t i v e : To determine the prevalence and risk factors of anti-tuberculosis drug resistance in Chiang Rai province where tuberculosis (TB) cases increased from 776 in 1987 to 1478 in 1997. Design: Population surveillance (province-wide) of drug resistance among sputum smear acid-fast bacilli (AFB) positive pulmonary TB cases was conducted prospectively since July 1996. Voluntary HIV testing and counseling has been an integral part of the surveillance system. Setting: All hospitals (including private hospitals) in the province participated in the surveillance. Participants: Consecutively recruited 839 TB cases with isolated Myco-
bacterium tuberculosis.
Interventions: None. Main Outcome Measure(s): Drug susceptibility testing was done blindly to the patient characteristics. Laboratory procedure was the proportional methc~ds standardized by WHO/IUATLD Global Project on Anti-TB Drug Resistance Surveillance. Results: Prevalence of drug resistance with no prior TB treatment (n = 745) to isoniazid (INH), rifampin (RFP), streptomycin (SM), ethambutol (EB), multi-drug (MDR, defined by resistance to both INH and RFP) was 14%, 13%, 17%, 8%, and 7.9%, respectively. Patients with prior TB treatment (n 94) had higher (p < 0.01 except EB: p - 0.20) prevalence of drug resistance to INH, RFP, SM, EB, MDR as 30%, 5:~%, 28%, 12%, and 22%, respectively. Among patients with no prior TB treatment, prevalence of MDR was significantly higher in persons with HIV-positivity (OR = 2.3, 95% CI[1.3-4.4], p = 0.004}, treatment at the provincial referral hospital (OR = 2.9, 95% CI[1.6-5.5], p = 0.002), and residence at central district (OR = 2.1,95% CI[1.2-L8], p = 0.008). Conclusions: TB control program should be strongly strengthened to increase cure rate and there should be increased monitoring of anti-TB drug resistance through continuous surveillance.
INFECTIOUS DISEASE
HIV INCIDENCE RATES AMONG DRUG USERS IN AN HIV EPICENTER IN NORTHERN THAI, LAND, 1 9 8 9 - 1 9 9 7 . P. Sawanpanyalert, S. Supawitkul, H. Yanai, P. Saksoong, S. Piyaworawong. Field Epidemiology T r a i n i n g Program, Ministry o f Public Health, Thailand; Mae C h a n Hospital, C h i a n g Rai, Thailand; Research Institute of Tuberculosis, Tokyo, Japan. Objective: To determine trends and associated risk factors of HIV incidence (1989-1997) in a drug abuse treatment clinic in northern Thailand where HIV is epidemic. Design: Retrospective cohort study of drug users who were initially HIVnegative and treated more than once. Nine years (1989-1997) of data (excluding names) from logbook were transcribed and double entered into two separate computer files and validated. For each patient, the dates of the first HIV-negative test, the last HIV-negative test, and the first HIVpositive tests were determined. Setting: Drug abuse treatment clinic at district level hospital. Participants: 378 repeat drug users who meet the criteria above in 19891997. Interventions: None. Main Outcome Measure(s): HIV incidence rate per 100 person-years of observation (PYO). HIV seroconversum was assumed to follow a uniform distribution between last negative and first positive HIV test. The 95% confidence interwll (C1) for the incidence was calculated using Poisson approximation method. Results: Of 378 repeat patients 16 (4.2%) converted to HIV positivity. This is equiw~lent to 5.1 per 100 PYO (95% CI = kl-8.4). The incidence remained relatively stable over the study period while the prevalence was on the decline. The younger (-<30 years old) had a higher incidence (10.7 per 100 PYO) than the older (2.7 per 100 PYO). The incidence was higher among Thai lowlanders (5.8 per 100 PYO) than other ethnic minorities (1.8 per 100 PYO). Drug injectors (8.0 per 100 PYO) had a higher incidence than drug smokers (2.6 per 100 PYO). Conclusions: Prevalence can give illusional results. It is necessary to know baseline HIV incidence to monitor and ew~luate an HIV intervention program,
IMMUNITY
FOR
YELLOW
FEVER
VIRUS
(YFV)
AS A RISK F A C T O R FOR D E N G U E HEMORR H A G I C F E V E R ( D H F ) . Luis Villar. C E U , Universidad Industrial de Santander, Bucaramanga, Colombia. O b j e c t i v e : To determine if patients with DHF are more predisposed to have immunity fi)r YFV than those with (Non-hemorrhagic) Dengue Classical Fever (DCF), since YF vaccine produces an immune response similar to a primary dengue infection and pathogenesis of DHF implicates consecutive infections by dengue virus. Design: Case-control study. Setting: The General Community Hospital at Bucaramanga, a general tertiary level referral center for the Santander province. Participants: Patients with acute dengue virus infection. 120 cases of DHF by World Health Organization criteria and 120 control patients who experienced the classical form of the illness. Interventions: A Neutralizing Antibody Test (NAT) for YFV immunity status. The primary or secondary dengue virus infection was defined through a haemagluttination inhibition test; clinical chart was reviewed to obtain information about clinical condition, confounding and risk factors. M a i n Outcome Measure(s): YFV immunity status. Results: The association among immunity for YFV and DHF was contemplated in a logistic regression model, as well as other important variables such as age, sex and kind of infection (primary or secondary infection). There was no relationship between YFV immunity and DHF (OR = 0.988; CI 95%: 0.996-1.006). The risk of having antibodies against YFV was higher in older than 15 years (OR = 2.572; CI 95%: 1.396-4.737), while living in the urban area was a protecting factor for YFV immunity (OR = 0.313;.CI 95%: 0.158-0.621). Conclusions: YFV immunity is not a risk factor for developing DHF in patients with acute infection by dengue virus.
ANTI-TUBERCULOSIS AN HIV EPIDEMIC
DRUG RESISTANCE PROVINCE, THAILAND.
IN' H.
Yanai, S. Supawitkul, N. Kunyanone, T. Yoshiyama, D. Rienthong, P. Akarasewi. International Epidemiologic Association, C h i a n g Rai Hospital, Thailand; Research Institute of Tuberculosis, Tokyo, Japan; TB division, M O P H , Bangkok, Thailand. O b j e c t i v e : To determine the prevalence and risk factors of anti-tuberculosis drug resistance in Chiang Rai province where tuberculosis (TB) cases increased from 776 in 1987 to 1478 in 1997. Design: Population surveillance (province-wide) of drug resistance among sputum smear acid-fast bacilli (AFB) positive pulmonary TB cases was conducted prospectively since July 1996. Voluntary HIV testing and counseling has been an integral part of the surveillance system. Setting: All hospitals (including private hospitals) in the province participated in the surveillance. Participants: Consecutively recruited 839 TB cases with isolated Myco-
bacterium tuberculosis.
Interventions: None. Main Outcome Measure(s): Drug susceptibility testing was done blindly to the patient characteristics. Laboratory procedure was the proportional methc~ds standardized by WHO/IUATLD Global Project on Anti-TB Drug Resistance Surveillance. Results: Prevalence of drug resistance with no prior TB treatment (n = 745) to isoniazid (INH), rifampin (RFP), streptomycin (SM), ethambutol (EB), multi-drug (MDR, defined by resistance to both INH and RFP) was 14%, 13%, 17%, 8%, and 7.9%, respectively. Patients with prior TB treatment (n 94) had higher (p < 0.01 except EB: p - 0.20) prevalence of drug resistance to INH, RFP, SM, EB, MDR as 30%, 5:~%, 28%, 12%, and 22%, respectively. Among patients with no prior TB treatment, prevalence of MDR was significantly higher in persons with HIV-positivity (OR = 2.3, 95% CI[1.3-4.4], p = 0.004}, treatment at the provincial referral hospital (OR = 2.9, 95% CI[1.6-5.5], p = 0.002), and residence at central district (OR = 2.1,95% CI[1.2-L8], p = 0.008). Conclusions: TB control program should be strongly strengthened to increase cure rate and there should be increased monitoring of anti-TB drug resistance through continuous surveillance.