Community-based active case finding for tuberculosis in rural western China: a cross-sectional study

SETTING

Current passive case finding strategies are not effective at identifying tuberculosis (TB) patients in rural China.

OBJECTIVE

To evaluate a community-based, active case finding (ACF) scheme in identifying symptomatic individuals with TB.

DESIGN

We conducted door-to-door household visits of all residents aged 15 years at two rural sites to screen for TB symptoms. Individuals with symptoms were enrolled and asked to provide three sputum samples. All participants underwent chest X-ray, and microbiologic detection of Mycobacterium tuberculosis from sputum samples using microscopy, solid culture and Xpert® MTB/RIF was performed.

RESULTS

Among the 19 334 residents screened for TB symptoms, 865 (4.5%) reported having 1 symptom. A total of 52 TB cases were detected, 11 of whom had microbiologic confirmation. Xpert identified all five M. tuberculosis culture-positive cases and yielded an additional three diagnoses. Prevalence of newly detected TB at the two sites through ACF was respectively 475 and 196 per 100 000 population. These estimates are respectively four and eight times, on average, higher than those identified through passive surveillance during the previous 5-year period for the two sites.

CONCLUSION

Community-based symptom screening followed by laboratory tests was found to be feasible and effective in increasing TB case finding in rural China.

Two-year study of the protective efficacy of the oral whole cell plus recombinant B subunit cholera vaccine in Peru

The protective efficacy of an oral inactivated whole cell Vibrio cholerae plus recombinant B subunit cholera vaccine was determined against El Tor cholera among Peruvian children and adults (2-65 years old) in a randomized, double-blind manner. Study subjects received 2 doses of vaccine or placebo 2 weeks apart, followed by a booster dose 10 months later. Surveillance for cholera was performed actively, with 2 visits per week to each household, and passively, at a local hospital. Stool samples were collected during diarrhea episodes and were cultured for V. cholerae. A total of 17,799 persons received 2 doses of vaccine or placebo, and 14,997 of these persons received the booster dose. After 2 doses (first surveillance period), V. cholerae biotype O1 was isolated from 17 vaccinees and 16 placebo recipients, demonstrating vaccine efficacy (VE) of -4%. After 3 doses (second surveillance period), V. cholerae O1 was isolated from 13 vaccinees and 32 placebo recipients, demonstrating VE of 61% (95% confidence interval ¿CI, 28%-79%). In the second surveillance period, the VE for illness requiring hospitalization was 82% (95% CI, 27%-96%). VE was also higher for persons >15 years old (VE, 72%; 95% CI, 28%-89%).

Safety, immunogenicity, and lot stability of the whole cell/recombinant B subunit (WC/rCTB) cholera vaccine in Peruvian adults and children

To assess the safety, immunogenicity, and lot stability of the whole cell/recombinant B subunit cholera vaccine, 2 lots manufactured in June 1991 and February 1992 were tested in January 1995. Two oral doses of vaccine or placebo given 2 weeks apart were given with buffer to 216 Peruvian adults and children. Symptoms were elicited for 3 days after each dose. Serum and plasma specimens obtained from each volunteer before vaccination and 10-14 days after the second dose were tested for vibriocidal and anti-cholera toxin antibodies. The vaccine was well-tolerated. Nearly half of the 100 vaccinees had pre-vaccination vibriocidal titers > or = 1:40. Elevated titers were observed in 22% of 37 children 2-5 years of age compared with 66% of 63 vaccinees 6-65 years (P < 0.001). A > or =2-fold serum vibriocidal response was observed in 55% of 100 vaccinees and 6% of 32 placebo recipients. An elevated pre-vaccination titer (< or =1:40) did not change the proportion of vaccinees who responded with a > or =2-fold increase in vibriocidal titer (51% versus 59%, difference not significant), but did change the proportion responding with a > or =4-fold increase (41% versus 22%; P < 0.05). The vibriocidal seroconversion rate was lowest in children 2-5 years old despite low pre-vaccination titers. Two-fold or greater serum antitoxic responses in IgA and IgG were observed in >90% of the vaccinees; > or =4-fold responses were seen in 65-70% of the vaccinees with a 6-8-fold increase over baseline. Plasma specimens were as good as sera for determining anti-toxic antibodies by ELISA, but were less satisfactory for determining vibriocidal antibody titers.

Transmission of HIV in dialysis centre

In August, 1993, 13 dialysis patients at one dialysis centre in Colombia, South America, were found to be HIV positive, and this prompted an epidemiological investigation. We carried out a cohort study of all dialysis centre patients during January, 1992 to December, 1993 (epidemic period) to determine risk factors for HIV seroconversion. Haemodialysis and medical records were reviewed, dialysis centre staff and surviving patients were interviewed, and dialysis practices were observed. Stored sera from all dialysis centre patients were tested for HIV antibody. 12 (52%) of 23 patients tested positive for HIV antibody by enzyme immunoassay and western blot during the epidemic period. Of the 23 tested, 9 (39%) converted from HIV antibody negative to positive (seroconverters) and 10 (44%) remained HIV negative (seronegatives). The HIV seroconversion rate was higher among patients dialysed at the centre while a new patient, who was HIV seropositive, was dialysed there (90% vs 0%; p < 0.01), or when the dialysis centre reprocessed access needles, dialysers, and bloodlines (60% vs 0%). While 2 of 9 HIV seroconverters had had sex with prostitutes, none had received unscreened blood products or had other HIV risk factors. No surgical or dental procedures were associated with HIV seroconversion. Dialysers were reprocessed separately with 5% formaldehyde and were labelled for use on the same patient. Access needles were reprocessed by soaking them in a common container with a low-level disinfectant, benzalkonium chloride; 4 pairs of needles were placed in one pan creating the potential for cross-contamination or use of one patient's needles on another patient. HIV transmission at the dialysis centre was confirmed. Improperly reprocessed patient-care equipment, most probably access needles, is the likely mechanism of transmission. This outbreak was discovered by accident and similar transmission may be occurring in many other countries where low-level disinfectants are used to sterilise critical patient-care equipment.

[Changes in the conditions for child survival in Mexico and strategies for the future]

Conditions of infant and child survival in Mexico have improved considerably over the last 60 years. Infant mortality rates were reduced from more than 250 deaths per 1,000 infants born alive in 1929-1931, to a rate of less than 50 in the period 1982-1987, a figure which still places Mexico among the countries with a high infant mortality rate. Though improvements in the living conditions of the population have undoubtedly played a part in the reduction of infant and child mortality, the early introduction of sanitation campaigns and, more recently of immunization, antibiotics and other modern health techniques have probably been more important. Health services have been extended throughout the country. However, significant portions of the population, especially in the rural areas, but also in the growing urban marginal ones, are to a large extent underserved. As a result, great inequalities in the health status of the population and in their access to health services remain. The problem of providing services to the whole population has become aggravated by the economic and financial crisis which has plagued Mexico since 1982. Reduced revenues for exports and the high cost of servicing the external and the internal debt have significantly decreased government revenues. As a result, public resources directed to health-related services diminished by 50 per cent in real terms between 1982 and 1987. This trend has to be reversed through enforced measures directed to the mobilization of untapped external and internal resources. But improving the conditions of child survival in Mexico requires more than financial resources. It is necessary to integrate and coordinate the fragmented services offered by the government, to give a much higher priority to preventive measures, and to research and to the adequate training of professionals and paraprofessionals in order to re-orient the health system for serving the real needs of the more underprivileged groups of the population (understanding and respecting their cultural beliefs and practices). In this way, Mexico can reverse the trend toward greater inequality which pervades the present system.

[Postneonatal mortality caused by diarrhea: a case-control study]

A matched case-control study was undertaken in Naucalpan de Juárez, Estado de México. The goal of this study was to identify the risk factors for diarrheal disease in children between seven days and one year of age. We identified 63 case and 188 controls. The most important risk factors were: mother's age greater than 36 years with an odds ratis (OR) 3.7, lack of breastfeeding (OR 11.3), breast and bottle feeding (OR 5.4), lack of intradomiciliary sewage (OR 8.3), repeated episoded of disease (OR 8.6) and father's consumption alcoholic beverages (OR 3.6). The main possible paths by which these factors influence mortality are discussed. Specific interventions for some of the factors are proposed.

Reiter's syndrome, immunodepression and strongyloidiasis. Report of a fatal case

We present the case of a 52-year-old white male who showed arthritis, conjunctivitis and non-gonococcal urethritis. Besides those manifestations, the patient also showed mucocutaneous lesions that were both clinically and histologically indistinguishable from those of pustular psoriasis. Due to the severity of the disease it was necessary to treat this patient with corticosteroids and immunosuppressors. With this therapy the clinical manifestations of Reiter's Syndrome disappeared but sudden abdominal and bronchopulmonary symptoms complicated the picture and the patient died in a septical shock. The autopsy findings revealed massive Strongyloidiasis with the presence of larvae in several organs, particularly in the intestinal wall, the lungs and the liver.