A high rate of recurrent tuberculosis in western Kenya independent of human immunodeficiency virus infection

Background: Previous studies have shown that recurrent TB develops in about 2-5% of the patients after curative treatment with short-course anti-TB chemotherapy. With the advent of HIV/AIDS, the rate TB recurrence is anticipated to rise. Objectives: To determine whether HIV infection and TB recurrence are associated with anti-TB drug resistance and the rates of ZN microscopy and culture positivity among the recurrent TB cases in western Kenya. Design and methods: A cross-sectional study was carried out between 2007 and 2009. Sputa from 872 tuberculosis suspects underwent mycobacteriologic evaluation using Ziehl Neelsen smear microscopy, LowensteinJensen and BACTEC MGIT 960 culturing, and Hain’s GenoType® Mycobacterium CM and GenoType® Mycobacterium AS molecular identification tests. Consenting participants were screened for HIV infection using Uni-Gold TM test and positives were confirmed with the enzyme linked immunosorbent assay. Results: In total, 361/872 (41%) of the suspects mycobacterial disease (346 TB, 4.2% non-tuberculous mycobacterial disease). HIV testing was accepted by 695 (79.7%) and 39.1% of these (272/695) were found positive. Recurrence of TB constituted 44.8% (155/346) of the TB cases, with 41.9% (65/155) of them co-infected with HIV. There was nosignificant difference in TB recurrence rates with HIV status [OR = 0.57; 95% CI: 0.29-1.13; P = 0.10]. Conclusions and recommendations: This study reports a much higher (44.8%) rate of recurrent TB, compared to that of National TB control Programme of 5% in 2008 and a combined retreatment rate of 14% in 2009. The HIV co-infection and TB recurrence were not associated with anti-TB drug resistance. The majority of TB recurrent cases were ZN smear negative (67.7%) and culture negative (80%). The high TB recurrence observed in this study calls for studies to determine the proportions of the disease attributable to endogenous re-activation (relapse) and exogenous re-infection. Keywords: Recurrent tuberculosis; HIV co-infectio

Impact of asymptomatic plasmodium falciparum infection on the risk of subsequent matic malaria in a longitudinal cohort in Kenya

Background: Asymptomatic Plasmodium falciparum infections are common in sub-Saharan Africa, but their effect on subsequent symptomaticity is incompletely understood. Methods: In a 29-month cohort of 268 people in Western Kenya, we investigated the association between asymptomatic P. falciparum and subsequent symptomatic malaria with frailty Cox models. Results: Compared to being uninfected, asymptomatic infections were associated with an increased 1-month likelihood of symptomatic malaria [adjusted Hazard Ratio (aHR):2.61, 95%CI:2.05–3.33], and this association was modified by sex, with females [aHR:3.71, 95%CI:2.62–5.24] at higher risk for symptomaticity than males [aHR:1.76, 95%CI:1.24–2.50]. This increased symptomatic malaria risk was observed for asymptomatic infections of all densities and in people of all ages. Long-term risk was attenuated but still present in children under 5 [29-month aHR:1.38, 95%CI:1.05–1.81]. Conclusions: In this high-transmission setting, asymptomatic P. falciparum can be quickly followed by symptoms and may be targeted to reduce the incidence of symptomatic illness

Exposure to Diverse Plasmodium falciparum Genotypes Shapes the Risk of Symptomatic Malaria in Incident and Persistent Infections: A Longitudinal Molecular Epidemiologic Study in Kenya

Background: Repeated exposure to malaria infections could protect against symptomatic progression as people develop adaptive immunity to infections acquired over time. Methods: We investigated how new, recurrent, and persistent Plasmodium falciparum infections were associated with the odds of developing symptomatic compared with asymptomatic malaria. Using a 14-month longitudinal cohort in Western Kenya, we used amplicon deep sequencing of 2 polymorphic genes (pfama1 and pfcsp) to assess overlap of parasite genotypes (represented by haplotypes) acquired within an individual's successive infections. We hypothesized infections with novel haplotypes would increase the odds of symptomatic malaria. Results: After excluding initial infections, we observed 534 asymptomatic and 88 symptomatic infections across 186 people. We detected 109 pfcsp haplotypes, and each infection was classified as harboring novel, recurrent, or persistent haplotypes. Incident infections with only new haplotypes had higher odds of symptomatic malaria when compared with infections with only recurrent haplotypes [odds ratio (OR): 3.24; 95% confidence interval (CI), 1.20-8.78], but infections with both new and recurrent haplotypes (OR: 0.64; 95% CI: 0.15-2.65) did not. Assessing persistent infections, those with mixed (persistent with new or recurrent) haplotypes (OR: 0.77; 95% CI: 0.21-2.75) had no association with symptomatic malaria compared with infections with only persistent haplotypes. Results were similar for pfama1. Conclusions: These results confirm that incident infections with only novel haplotypes were associated with increased odds of symptomatic malaria compared with infections with only recurrent haplotypes but this relationship was not seen when haplotypes persisted over time in consecutive infections

NOSOCOMIAL INFECTIONS IN DEVELOPING COUNTRIES: COST EFFECTIVE CONTROL AND PREVENTION

Objectives: To review the efficient and cost-effective preventive, control and surveillancemeasures that could be employed against nosocomial infections in developing countries.Data sources: Literature search on compact disk-read only memory (CD-ROM), Medlineand Internet, using the key words: nosocomial infection, prevention and control, useof antibiotics and use of computers. Some articles were manually reviewed.Study selection: Relevant studies or articles on nosocomial infections in developing anddeveloped countries were included in the review.Data extraction: From individual studies or articles.Data synthesis: Information on nosocomial infections from developing and developedcountries with some emphasis on Kenya is synchronized under the headings; introduction,historical background of nosocomial infections. Current situation of nosocomial infectionsand predisposing factors, nosocomial infections and antimicrobial resistance, consequencesof nosocomial infections, hospital infection control programme and use of computersin nosocomial infection surveillance, and the cost benefit of infection prevention andcontrol programme.Conclusion: Nosocomial infections may be contained more effectively by having aninfection prevention and control programme. Computer-assisted epidemiologicalsurveillance appears to be the most important aspect of monitoring infection controlprogrammes, and to identify changes in risk factors that can increase the infection rate.Even minimally, effective infection control programmes are cost-effective. For the waragainst nosocomial infections to be won, the whole exercise should be handled as a globalproject with significant inputs from developing countries