Typhoid outbreak investigation in Dzivaresekwa, suburb of Harare City, Zimbabwe, 2011

Introduction: Typhoid fever is a systemic infection caused by a Gram negative bacterium, Salmonella  typhi. Harare City reported 1078 cases of suspected typhoid fever cases from October  011 to January 2012. We initiated an investigation to identify possible source of transmission so as to institute control measures. Methods: An unmatched 1:1 case-control study was conducted. A questionnaire was administered to study participants to identify risk factors for contracting typhoid. A case was a resident of Dzivaresekwa who presented with signs and symptoms of typhoid between October and December 2011. Water  samples were collected for microbiological analysis. Results: 115 cases and 115 controls were enrolled. Drinking water from a well (OR= 6.2 95% CI  (2.01-18.7)), attending a gathering (OR= 11.3 95% CI (4.3-29.95)), boiling drinking water (OR= 0.21 95% CI (0.06-0.76)) and burst sewer pipe at home (OR= 1.19 95% CI (0.67-2.14)) were factors  associated with contracting typhoid. Independent risk factors for contracting typhoid were drinking water from a well (AOR=5.8; 95% CI (1.90-17.78)), and burst sewer pipe at home (AOR=1.20; 95% CI (1.10-2.19)). Faecal coli forms and E. coli were isolated from 8/8 well water samples. Stool, urine and blood specimens were cultured and serotyped for Salmonella typhi and 24 cases were confirmed positive. Shigella, Giardia and E coli were also isolated. Ciprofloxacin, X-pen and Rocephin were used for case  management. No complications were reported. Conclusion: Contaminated water from unprotected water sources was the probable source of the  outbreak. Harare City Engineer must invest in repairing water and sewage reticulation systems in the city.Key words: Typhoid, outbreak investigation, contaminated water, Zimbabwe

Provider-initiated symptom screening for tuberculosis in Zimbabwe: diagnostic value and the effect of HIV status.

OBJECTIVE: To assess the diagnostic value of provider-initiated symptom screening for tuberculosis (TB) and how HIV status affects it. METHODS: We performed a secondary analysis of randomly selected participants in a community-based TB-HIV prevalence survey in Harare, Zimbabwe. All completed a five-symptom questionnaire and underwent sputum TB culture and HIV testing. We calculated the sensitivity, specificity, and positive and negative predictive values of various symptoms and used regression analysis to investigate the relationship between symptoms and TB disease. FINDINGS: We found one or more symptoms of TB in 21.2% of 1858 HIV-positive (HIV+) and 9.9% of 7121 HIV-negative (HIV-) participants (P or = 2 weeks' duration, any symptom and a positive sputum culture had sensitivities of 48%, 81% and 65%, respectively; in HIV- participants, the sensitivities were 45%, 71% and 74%, respectively. Symptoms had a similar sensitivity and specificity in HIV+ and HIV- participants, but in HIV+ participants they had a higher positive and a lower negative predictive value. CONCLUSION: Even smear-positive TB may be missed by provider-initiated symptom screening, especially in HIV+ individuals. Symptom screening is useful for ruling out TB, but better TB diagnostics are urgently needed for resource-poor settings

Implementation and Operational Research: The Effectiveness of Routine Opt-Out HIV Testing for Children in Harare, Zimbabwe.

OBJECTIVE: HIV testing is the entry point to access HIV care. For HIV-infected children who survive infancy undiagnosed, diagnosis usually occurs on presentation to health care services. We investigated the effectiveness of routine opt-out HIV testing (ROOT) compared with conventional opt-in provider-initiated testing and counseling (PITC) for children attending primary care clinics. METHODS: After an evaluation of PITC services for children aged 6-15 years in 6 primary health care facilities in Harare, Zimbabwe, ROOT was introduced through a combination of interventions. The change in the proportion of eligible children offered and receiving HIV tests, reasons for not testing, and yield of HIV-positive diagnoses were compared between the 2 HIV testing strategies. Adjusted risk ratios for having an HIV test in the ROOT compared with the PITC period were calculated. RESULTS: There were 2831 and 7842 children eligible for HIV testing before and after the introduction of ROOT. The proportion of eligible children offered testing increased from 76% to 93% and test uptake improved from 71% to 95% in the ROOT compared with the PITC period. The yield of HIV diagnoses increased from 2.9% to 4.5%, and a child attending the clinics post intervention had a 1.99 increased adjusted risk (95% CI: 1.85 to 2.14) of receiving an HIV test in the ROOT period compared with the preintervention period. CONCLUSION: ROOT increased the proportion of children undergoing HIV testing, resulting in an overall increased yield of positive diagnoses, compared with PITC. ROOT provides an effective approach to reduce missed HIV diagnosis in this age group

Validation of a screening tool to identify older children living with HIV in primary care facilities in high HIV prevalence settings.

OBJECTIVE: We previously proposed a simple tool consisting of five items to screen for risk of HIV infection in adolescents (10-19 years) in Zimbabwe. The objective of this study is to validate the performance of this screening tool in children aged 6-15 years attending primary healthcare facilities in Zimbabwe. METHODS: Children who had not been previously tested for HIV underwent testing with caregiver consent. The screening tool was modified to include four of the original five items to be appropriate for the younger age range, and was administered. A receiver operator characteristic analysis was conducted to determine a suitable cut-off score. The sensitivity, specificity and predictive value of the modified tool were assessed against the HIV test result. RESULTS: A total of 9568 children, median age 9 (interquartile, IQR: 7-11) years and 4971 (52%) men, underwent HIV testing. HIV prevalence was 4.7% (95% confidence interval, CI:4.2-5.1%) and increased from 1.4% among those scoring zero on the tool to 63.6% among those scoring four (P < 0.001). Using a score of not less than one as the cut-off for HIV testing, the tool had a sensitivity of 80.4% (95% CI:76.5-84.0%), specificity of 66.3% (95% CI:65.3-67.2%), positive predictive value of 10.4% and a negative predictive value of 98.6%. The number needed to screen to identify one child living with HIV would drop from 22 to 10 if this screening tool was used. CONCLUSION: The screening tool is a simple and sensitive method to identify children living with HIV in this setting. It can be used by lay healthcare workers and help prioritize limited resources

Barriers to provider-initiated testing and counselling for children in a high HIV prevalence setting: a mixed methods study.

BACKGROUND: There is a substantial burden of HIV infection among older children in sub-Saharan Africa, the majority of whom are diagnosed after presentation with advanced disease. We investigated the provision and uptake of provider-initiated HIV testing and counselling (PITC) among children in primary health care facilities, and explored health care worker (HCW) perspectives on providing HIV testing to children. METHODS AND FINDINGS: Children aged 6 to 15 y attending six primary care clinics in Harare, Zimbabwe, were offered PITC, with guardian consent and child assent. The reasons why testing did not occur in eligible children were recorded, and factors associated with HCWs offering and children/guardians refusing HIV testing were investigated using multivariable logistic regression. Semi-structured interviews were conducted with clinic nurses and counsellors to explore these factors. Among 2,831 eligible children, 2,151 (76%) were offered PITC, of whom 1,534 (54.2%) consented to HIV testing. The main reasons HCWs gave for not offering PITC were the perceived unsuitability of the accompanying guardian to provide consent for HIV testing on behalf of the child and lack of availability of staff or HIV testing kits. Children who were asymptomatic, older, or attending with a male or a younger guardian had significantly lower odds of being offered HIV testing. Male guardians were less likely to consent to their child being tested. 82 (5.3%) children tested HIV-positive, with 95% linking to care. Of the 940 guardians who tested with the child, 186 (19.8%) were HIV-positive. CONCLUSIONS: The HIV prevalence among children tested was high, highlighting the need for PITC. For PITC to be successfully implemented, clear legislation about consent and guardianship needs to be developed, and structural issues addressed. HCWs require training on counselling children and guardians, particularly male guardians, who are less likely to engage with health care services. Increased awareness of the risk of HIV infection in asymptomatic older children is needed

Burden of HIV among primary school children and feasibility of primary school-linked HIV testing in Harare, Zimbabwe: a mixed methods study.

Population-based surveys in Southern Africa suggest a substantial burden of undiagnosed HIV-infected long-term survivors of mother-to-child transmission. We conducted an HIV prevalence survey of primary school pupils in Harare, Zimbabwe, and evaluated school-linked HIV counselling and testing (HCT) for pupils, their families and schoolteachers. Population-weighted cluster sampling was used to select six primary schools. Randomly selected class-grade pupils underwent anonymous HIV testing, with concurrent school-linked family HCT offered during the survey. Focus group discussions and interviews were conducted with pupils, parents/guardians, counsellors, and schoolteachers. About 4386 (73%) pupils provided specimens for anonymous HIV testing. Median age was 9 years (IQR 8-11), and 54% were female. HIV prevalence was 2.7% (95% CI: 2.2-3.1) with no difference by gender. HIV infection was significantly associated with orphanhood, stunting, wasting, and being one or more class grades behind in school due to illness (p<0.001). After adjusting for covariates, orphanhood and stunting remained significantly associated with being HIV positive (p<0.001). Uptake of diagnostic HIV testing by pupils was low with only 47/4386 (1%) pupils undergoing HCT. The HIV prevalence among children under 15 years who underwent HIV testing was 6.8%. The main barrier to HIV testing was parents' fear of their children experiencing stigma and of unmasking their own HIV status should the child test HIV positive. Most guardians believed that a child's HIV-positive result should not be disclosed and the child could take HIV treatment without knowing the reason. Increased recognition of the high burden of undiagnosed HIV infection in children is needed. Despite awareness of the benefits of HIV testing, HIV-related stigma still dominates parents/guardians' psychological landscape. There is need for comprehensive information and support for families to engage with HIV testing services

The Risk and Timing of Tuberculosis Diagnosed in Smear-Negative TB Suspects: A 12 Month Cohort Study in Harare, Zimbabwe

BACKGROUND: Cases of smear-negative TB have increased dramatically in high prevalence HIV settings and pose considerable diagnostic and management challenges. METHODS AND FINDINGS: Between February 2006 and July 2007, a cohort study nested within a cluster-randomised trial of community-based case finding strategies for TB in Harare, Zimbabwe was undertaken. Participants who had negative sputum smears and remained symptomatic of TB were follow-up for one year with standardised investigations including HIV testing, repeat sputum smears, TB culture and chest radiography. Defaulters were actively traced to the community. The objectives were to investigate the incidence and risk factors for TB. TB was diagnosed in 218 (18.2%) participants, of which 39.4% was bacteriologically confirmed. Most cases (84.2%) were diagnosed within 3 months, but TB incidence remained high thereafter (111.3 per 1000 person-years, 95% CI: 86.6 to 146.3). HIV prevalence was 63.3%, and HIV-infected individuals had a 3.5-fold higher risk of tuberculosis than HIV-negative individuals. CONCLUSION: We found that diagnosis of TB was insensitive and slow, even with early radiography and culture. Until more sensitive and rapid diagnostic tests become widely available, a much more proactive and integrated approach towards prompt initiation of ART, ideally from within TB clinics and without waiting for TB to be excluded, is needed to minimise the risk and consequences of diagnostic delay

High post-exposure prophylaxis uptake but low completion rates and HIV testing follow-up in health workers, Harare, Zimbabwe.

INTRODUCTION: Health care workers (HCWs), especially from sub-Saharan Africa, are at risk of occupational exposure to HIV. Post exposure prophylaxis (PEP) can reduce this risk. There is no published information from Zimbabwe, a high HIV burden country, about how PEP works. We therefore assessed how the PEP programme performed at the Parirenyatwa Hospital, Harare, Zimbabwe, from 2017-2018. METHODOLOGY: This was a cohort study using secondary data from the staff clinic paper-based register. The chi square test and relative risks were used to assess associations. RESULTS: There were 154 HCWs who experienced occupational injuries. The commonest group was medical doctors (36%) and needle sticks were the most frequent type of occupational injury (74%). The exposure source was identified in 114 (74%) occupational injuries: 91% of source patients were HIV-tested and 77% were HIV-positive. All but two HCWs were HIV-tested, 148 were eligible for PEP and 142 (96%) started triple therapy, all within 48 hours of exposure. Of those starting PEP, 15 (11%) completed 28 days, 13 (9%) completed < 28 days and in the remainder PEP duration was not recorded. There were no HCW characteristics associated with not completing PEP. Of those starting PEP, 9 (6%) were HIV-tested at 6-weeks, 3 (2%) were HIV-tested at 3-months and 1 (< 1%) was HIV-tested at 6-months: all HIV-tests were negative. CONCLUSIONS: While uptake of PEP was timely and high, the majority of HCWs failed to complete the 28-day treatment course and even fewer attended for follow-up HIV-tests. Various changes are recommended to promote awareness of PEP and improve adherence to guidelines

Detection of Mycobacterium tuberculosis in Sputum by Gas Chromatography-Mass Spectrometry of Methyl Mycocerosates Released by Thermochemolysis

Tuberculosis requires rapid diagnosis to prevent further transmission and allow prompt administration of treatment. Current methods for diagnosing pulmonary tuberculosis lack sensitivity are expensive or are extremely slow. The identification of lipids using gas chromatography- electron impact mass spectrometry (GC-EI/MS) could provide an alternative solution. We have studied mycocerosic acid components of the phthiocerol dimycocerosate (PDIM) family of lipids using thermochemolysis GC-EI/MS. To facilitate use of the technology in a routine diagnostic laboratory a simple extraction procedure was employed where PDIMs were extracted from sputum using petroleum ether, a solvent of low polarity. We also investigated a method using methanolic tetramethylammonium hydroxide, which facilitates direct transesterification of acidic components to methyl esters in the inlet of the GC-MS system. This eliminates conventional chemical manipulations allowing rapid and convenient analysis of samples. When applied to an initial set of 40 sputum samples, interpretable results were obtained for 35 samples with a sensitivity relative to culture of 94% (95%CI: 69.2,100) and a specificity of 100% (95%CI: 78.1,100). However, blinded testing of a larger set of 395 sputum samples found the assay to have a sensitivity of 61.3% (95%CI: 54.9,67.3) and a specificity of 70.6% (95%CI: 62.3,77.8) when compared to culture. Using the results obtained we developed an improved set of classification criteria, which when applied in a blinded re-analysis increased the sensitivity and specificity of the assay to 64.9% (95%CI: 58.6,70.8) and 76.2% (95%CI: 68.2,82.8) respectively. Highly variable levels of background signal were observed from individual sputum samples that inhibited interpretation of the data. The diagnostic potential of using thermochemolytic GC-EI/MS of PDIM biomarkers for diagnosis of tuberculosis in sputum has been established; however, further refinements in sample processing are required to enhance the sensitivity and robustness of the test