Transmission of tuberculosis to contacts of sputum positive adults in Malawi.

Over a period of one year from June 1993 to May 1994, 282 children under 6 years old who were household contacts of sputum positive adults with tuberculosis were evaluated in a screening clinic. Of these, 180 (63.8%) had evidence of tuberculosis, a much higher transmission rate than reported elsewhere. HIV seropositivity was 77.4% in the adult index cases and 18% in the contact children. No increased infectivity to household contacts was detected in HIV seropositive index adults compared with those who were seronegative. Child tuberculosis contact tracing is essential in these families, where transmission of disease is higher than reported elsewhere, and attention to the health needs of the children may be diminished by the high morbidity and mortality among adult family members.     

Risk factors for TB infection and disease in young childhood contacts in Malawi

BACKGROUND: Screening of children in household contact with smear-positive tuberculosis (TB) is universally recommended but seldom practiced in resource-poor settings. It has huge potential to reduce the burden of TB disease in children, particularly if streamlined to focus on those at greatest risk.AIMS: To assess the prevalence of infection and disease amongst children aged < or = 5 yrs in household contact with smear-positive TB. To identify which source case characteristics are risk factors for infection. METHODS: A prospective, hospital-based audit was conducted over a 17-mth period in Southern Malawi. Smear-positive adults were identified and encouraged to bring their children to the outpatient clinic, in accordance with the national TB programme guidelines. Full assessment was performed, including tuberculin skin test. RESULTS: 195 children aged < or = 5 yrs who were contacts of 161 source cases were assessed. Prevalences of TB infection and disease were high (45% and 23%, respectively). The likelihood of a child being infected was significantly greater with increasing smear-positivity of the source case, and also if the source case were female (OR 2.25, 95% CI 1.19-4.27, p = 0.01). CONCLUSIONS: The high prevalence of TB infection and disease in child contacts attending this hospital-based clinic supports the current policy of contact-screening in Malawi. However, community-based studies are needed to provide a more accurate assessment of prevalence and risks for child contacts.     

Transmission of multidrug-resistant tuberculosis

AIM: To compare the Mycobacterium tuberculosis isolates of adult index cases with multidrug-resistant (MDR) tuberculosis to the isolates obtained from their child contacts. PATIENTS AND METHODS: A 4-year prospective study in the Western Cape Province of South Africa. We evaluated 149 child contacts of 80 adult MDR pulmonary tuberculosis cases. This report includes those cases where a culture for M. tuberculosis was obtained from both the adult source case and the child contact. Isolates were compared by drug susceptibility pattern and restriction fragment length polymorphism analysis. RESULTS: Six adult-child pairs with cultures for M. tuberculosis were identified. Two children had contact with more than one adult tuberculosis case. One child received previous isoniazid prophylaxis. Drug susceptibility pattern and restriction fragment length polymorphism analysis were identical for five adult-child pairs. One child, with no other known source case, had a strain different from that of the identified source case, but the MDR M. tuberculosis strain with which he was infected was prevalent in the community in which he resided. All children responded well to treatment. CONCLUSION: This study confirms that most of the childhood contacts of adults with MDR tuberculosis are likely to be infected by these MDR source cases despite their exposure to other drug-susceptible adults with tuberculosis in some instances. Child contacts of adults with MDR tuberculosis should be treated according to the drug susceptibility patterns of the likely source cases' M. tuberculosis strains unless their own strain's susceptibility testing indicates otherwise. Contact tracing remains of fundamental importance in identifying children at risk.     

Diagnosis of pulmonary tuberculosis in children in an HIV-endemic area, Malawi

The diagnosis of pulmonary tuberculosis (PTB) in young children is particularly complex in resource-poor regions where HIV infection is common. This study examines the impact of HIV infection on diagnosis in children with suspected PTB attending Queen Elizabeth Central Hospital, Blantyre. A total of 110 children (4 months-14 years) were studied over a 4-month period. Clinical data were recorded and investigations included Mantoux test, chest X-ray, HIV status (HIV-PCR when younger than 18 months) and sputum, if available. Laryngeal swabs were compared with sputa or gastric aspirates in a subgroup of 60 children. All children were commenced on anti-TB therapy and followed for treatment response. Aware of the clinical overlap between HIV and TB infection, we used more limited criteria than recommended to allocate a final diagnosis following review of all data except HIV status. Final diagnosis included confirmed PTB (n = 8), probable PTB (n = 41), lymphocytic interstitial pneumonitis (n = 10), pulmonary Kaposi sarcoma (n = 3) and bronchiectasis (n = 5). Culture rates of M. tuberculosis were: five (27.8%) of 18 sputa, three (7.1%) of 42 gastric aspirates and four (6.6%) of 60 laryngeal swabs. The HIV infection rate was 70.6% overall and 57.8% in 45 children with confirmed or probable PTB. Although a positive contact history was more common in HIV-infected children, a final diagnosis of confirmed or probable PTB was less common than in HIV-uninfected children (36% vs 63%; p = 0.02). The Mantoux test was positive in 14 (19%) of 72 HIV-infected compared with 15 (50%) of 30 HIV-uninfected children (p < 0.01). A final diagnosis could not be made in 43 (39%) of the study children with suspected PTB, the majority of whom were HIV-infected. HIV-infected children had a significantly poorer response to TB treatment and higher lost-to-follow-up rates.     

Transmission of mycobacterium tuberculosis to and from children and adolescents

Although adult-type pulmonary tuberculosis frequently arises from a long-dormant infection with Mycobacterium tuberculosis, children usually develop tuberculosis as a direct complication of the initial infection. Adults with pulmonary tuberculosis frequently are infectious, but children with typical primary tuberculosis—enlarged hilar or mediastinal lymph nodes with or without bronchial obstruction and subsequent atelectasis—rarely, if ever, transmit the organism to others. This article reviews the pathophysiology of pediatric tuberculosis and the published evidence concerning transmission of M tuberculosis to and from children and adolescents. Children with congenital tuberculosis or older children with the characteristics of adult-type tuberculosis should be considered potentially infectious. However, there is no evidence that children with primary-type tuberculosis infect other individuals. Recommendations are made concerning the handling of children with suspected tuberculosis and their family members in pediatric healthcare settings. Copyright © 2001 by W.B. Saunders Company     

Evaluation of household contacts of children with positive tuberculin skin tests

BACKGROUND: Associate investigation, defined as screening the contacts of children with positive tuberculin skin tests (TST) and normal chest radiographs, has been recommended to improve case finding for active tuberculosis (TB). The success of this strategy has not been adequately studied in either adults or children. METHODS: A 2-year prospective study was conducted wherein 187 children and adolescents with infection caused by Mycobacterium tuberculosis (positive TST and normal chest radiograph) were referred to a TB Screening Clinic. An associate investigation was performed among their 659 household contacts who were interviewed to assess risk factors for TB and screened with TSTs and with chest radiographs when appropriate. RESULTS: No cases of active TB were detected, but 32% of household contacts had TSTs > or = 10 mm and were candidates for preventive therapy. Logistic regression analysis revealed that household contacts with Calmette-Guérin bacillus immunization and foreign birth were 2.26 and 3.92 times more likely (P < 0.001 and 0.002, respectively) to be tuberculin-positive. Univariate analysis of the 187 households revealed that the following risk factors present in a household member were associated with detecting a household contact with a positive TST: Calmette-Guérin bacillus immunization (P = 0.001), foreign birth (P = 0.017) and a history of having hosted foreign visitors (P = 0.032). CONCLUSION: In this Hispanic immigrant population, primarily from the Dominican Republic, screening household contacts of children with positive TSTs did not identify new cases of active TB. However, this strategy did identify household contacts who were eligible for preventive therapy.     

Failure of chemoprophylaxis with standard antituberculosis agents in child contacts of multidrug-resistant tuberculosis cases

BACKGROUND: There is little published information on optimal chemoprophylaxis for children with multidrug-resistant tuberculosis (MDR-TB) contacts. Current guidelines of World Health Organization suggest that isoniazid (INH), the standard first-line chemoprophylaxis, be used for those exposed to MDR-TB. METHODS: This is a retrospective review of medical records of 5 children residing in the Western Cape Province, South Africa, who developed MDR-TB while receiving conventional chemoprophylaxis with either INH or a combination of INH, rifampin, and pyrazinamide. RESULTS: Adult MDR-TB source cases were identified for all children and resistance patterns of patient and source case isolates matched in all cases. The median age of the patients was 0.4 years. One patient participated in a trial of INH chemoprophylaxis for HIV-infected children. Four HIV-uninfected infants presented with TB-related symptoms several months after being given chemoprophylaxis because of a known source case. Stigmata of TB were cough >3 weeks in 4, weight loss or a history of failing to thrive in 3, fever in 2 infants, and reported night sweats in 1. Chest radiographs at diagnosis revealed lymphadenopathy, lobar opacification, and airway narrowing. All patients were treated for varying time periods at a TB referral institution in the Western Cape. CONCLUSIONS: Standard, first-line anti-TB agents were inadequate to prevent MDR-TB in children exposed to MDR-TB contacts. Second-line chemoprophylaxis, reflecting the susceptibility profile of the source case's isolate, with at least 2 drugs with activity against the drug-resistant isolate for 6-12 months should be considered.     

Evaluation of Mycobacterium tuberculosis transmission from a pediatrician and initial compliance to prophylaxis of contacts in an outpatient pediatric clinic

OBJECTIVE: The risk that latent infection will progress to active tuberculosis is greater in infants and children than for most other age groups. We set out to determine the rate of transmission of Mycobacterium tuberculosis to pediatric patients exposed to a pediatrician with smear-negative and culture-positive pulmonary tuberculosis. We also explored factors associated with compliance to prophylaxis. METHODS: Clinic and hospital billing records were used to identify patients age 5 or less who were seen during the pediatrician's potential contagious period. Patient were notified by registered mail of their putative exposure and were offered a tuberculin skin test screening with 5 tuberculin units of purified protein derivative (Tubersol, Connaught) and chest radiography of children with a tuberculin skin test > or =5 mm. RESULTS: A total of 456 patients were identified as exposed; 140 contacts never responded for evaluation and 93 letters were not delivered because of incorrect mailing addresses. Of the 223 who completed screening 1 (0,4%) had a initial skin test result of 8 mm. The remaining 222 contacts had repeated negative test results. The only positive child (15 months old) was born in Honduras and had received Calmette-Guerin bacillus at birth. No active tuberculosis cases were identified in the 456 contacts up to 2 years after exposure. Compliance with prophylaxis was associated with having two or less children in the household (odds ratio, 2.5; 95% confidence interval, 1.1 to 5.9). CONCLUSION: We found no evidence of transmission of M. tuberculosis in an outpatient pediatric setting. Only 43% of exposed children completed screening, and 38% of those offered prophylaxis completed their initial 3 months of therapy.     

Transmission of tuberculosis from a seven-year-old child in a Sydney school

OBJECTIVES: To determine whether a 7-year-old child with extrapulmonary and pulmonary tuberculosis (TB) and direct smear positive sputum for acid-fast bacilli was infectious to home and school contacts, and to ascertain potential adult sources of infection for these contacts. METHODS: Contact tracing by Mantoux testing was conducted on 220 children at a primary school and after-school care facility, and 59 selected adults considered potential sources of infection. RESULTS: The participation rate for the children was 98% and 92% for the adults. Mantoux positivity (induration >/= 10 mm, or >/= 15 mm with previous BCG) among children was 13% at the school (anticipated rate 2-3%), 26% among school staff, and 7% among children at the after-school care centre where the index case attended. One exposed adult hospital staff member converted from Mantoux negative to positive. No other cases of TB disease were detected among children or adults tested. CONCLUSION: Although spread of TB from children to others is rare, the findings of this investigation indicate that transmission of TB from a young child to other children and an adult may have occurred, and that sputum testing and contact tracing for sputum smear positive children should be considered.     

Effect of zinc on the tuberculin response of children exposed to adults with smear-positive tuberculosis

The tuberculin test (PPD) is used frequently in the diagnosis of tuberculosis. PPD, however, relies on an intact cell-mediated immunity and infected children often have false negative results. This study assessed whether a single oral zinc supplement modifies the PPD induration size and its association with nutritional status in Brazilian children. Ninety-eight children below 15 years of age who had been exposed to adults with smear-positive pulmonary TB in 1998 were tested by PPD in 1998 and 2000. Children were randomised in 2000 to receive a single oral dose of zinc sulphate or a placebo at the time of administering the PPD. Forty-three (44%) children were PPD-positive in 1998 and 54 (55%) in 2000. A higher proportion of children were classified as PPD-positive in 2000 in the zinc-supplemented group (57.1%) than in the placebo group (53.1%). PPD indurations were larger in children receiving zinc (mean 18.5 and 15.5 mm in the zinc and placebo groups, respectively) (p < 0.03). Mean induration sizes in 2000 were larger in zinc-supplemented children, regardless of their nutritional status. Our study demonstrates that zinc increases the PPD induration size in children irrespective of nutritional state. Zinc supplementation could work by correcting asymptomatic or marginal zinc deficiencies or as a non-specific booster of immunological mechanisms (whether or not there is a deficiency).     

1992-2004年全国儿童新发现的痰涂片阳性肺结核监测与分析

目的 分析我国0～14岁儿童新发现的痰涂片阳性（简称新涂阳）肺结核患者监测报告现状,了解儿童结核病患病和发现趋势,进一步认识儿童结核病监测的流行病学意义,以及在现代结核病控制策略下,如何重视和加强儿童结核病防治的问题。方法根据1992-2004年全国结核病监测年报中0～14岁儿童新涂阳肺结核患者登记报告资料,分析我国儿童新涂阳肺结核患者占全国新涂阳肺结核患者的比例、新涂阳肺结核患者登记率,分析我国东部、中部、西部和京津沪地区以及除京津沪地区以外,自1992年开始实施现代结核病控制策略（DOTS）的世界银行贷款中国结核病控制项目的13省（简称项目地区）与未实施该策略的另15省（简称非项目地区）的新涂阳肺结核患者登记情况。结果1992-2004年,登记的0～14岁儿童新涂阳肺结核患者31358例,男14727例（47％）,女16631例（53％）。占同期新涂阳患者总数的1．26％,男0．89％,女2．03％（P〈0．01）。儿童新涂阳肺结核患者登记率在0．42／10万～1．08／10万之间。在全国不同地区登记的儿童新涂阳肺结核患者中,西部地区占44．9％,其次为中部和东部地区,京津沪占0．9％。除京津沪外,1992年开始实施DOTS策略的项目地区与非项目地区比较,0～14岁儿童新涂阳肺结核患者登记数分别占75％和25％。各年度儿童新涂阳肺结核患者数占总涂阳肺结核患者数的比例,以西部地区最高。结论在登记的儿童新涂阳肺结核患者中,女性儿童新涂阳肺结核患者登记数高于男性,女性儿童新涂阳肺结核患者占女性总新涂阳肺结核患者比例高于男性。西部地区儿童新涂阳肺结核患者数多于中部和东部地区,项目地区多于非项目地区。儿童涂阳肺结核患者的患病和发现,不仅与当地结核病疫情有关,还与是否实施现代结核病控制策略有着密切的关系。     

Incidence of retinoblastoma in Malawi.

The annual incidence of retinoblastoma in Malawi seems to be two cases per 100,000 children under five or one case per 10,000 live births. A higher frequency of one case per 21,700 to 17,900 children under five or one per 4,340 to 3,580 live births has been found in the Zomba and Mangochi districts. Analyzing the cases according to sex and laterality, 61.1 percent of the unilateral cases were girls and 58.3 percent of the bilaterals were boys. Among boys, 33.3 percent were bilateral while unilateral involvement of the left eye was found in 19.1 percent. Among the girls, the frequency of bilateral cases was 18.5 percent while the unilateral involvement of right and left eye was nearly similar.     

Supporting children to adhere to anti-retroviral therapy in urban Malawi: multi method insights

Background  

Ensuring good adherence is critical to the success of anti-retroviral treatment (ART). However, in resource-poor contexts, where paediatric HIV burden is high there has been limited progress in developing or adapting tools to support adherence for HIV-infected children on ART and their caregivers. We conducted formative research to assess children's adherence and to explore the knowledge, perceptions and attitudes of caregivers towards children's treatment.     

Intensive nursing care of kwashiorkor in Malawi

The case fatality rate for children with kwashiorkor in central hospitals in Malawi was 30.5% (275/901) in 1995. The purpose of this study was to determine whether improved case management with intensive nursing care could lower this case fatality rate. A total of 75 children admitted with kwashiorkor in Blantyre, Malawi, received intensive nursing care. This included nursing in individual clean beds with blankets, a nurse:child ratio of 1:3, supervised feedings every 2 h, a paediatrician with expertise in treating kwashiorkor always available for consultation, laboratory evaluation for systemic infection and empiric use of ceftriaxone. Nineteen of these children died (25%). The causes of death were life threatening electrolyte abnormalities (hypokalaemia, hyponatraemia, hypophosphataemia) in nine cases, overwhelming infection in eight cases and congestive heart failure in two children. Children infected with the human immunodeficiency virus were more likely to die (9/20), as were children with life threatening electrolyte abnormalities (9/15) and children with more severe wasting. When compared with 225 children treated in the same year at the same institution, who were carefully matched for severity of kwashiorkor, intensive nursing did not improve overall survival.