Microbiological investigation for tuberculosis among HIV-infected children in Soweto, South Africa

SETTING

A paediatric human immunodeficiency virus (HIV) clinic in an academic hospital in Soweto, South Africa.

OBJECTIVES

1) To describe and compare the clinical, immunological and virological characteristics of HIV-infected children co-treated for tuberculosis (TB), and 2) to compare those investigated microbiologically with those who were not, with a description of the results of the microbiological TB investigation.

DESIGN

Retrospective analysis of TB-HIV-infected children aged <15 years treated for TB between 1 October 2007 and 15 March 2009.

RESULTS

Anti-tuberculosis treatment was initiated in 616/3358 (18%) children during the study period. Microbiological TB investigation results were available for 399/616 (65%), among whom culture-confirmed TB was diagnosed in 49 (12%). Drug susceptibility testing was performed in 29/49 (59%) children: 5/29 (17%) were isoniazid-resistant, and 3 had multidrug-resistant TB. Children aged >8 years and those between 3 and 8 years were more likely to have culture-confirmed TB than those aged <3 years (aOR 9.4, 95%CI 2.26-39.08 vs. aOR 6.7, 95%CI 1.60-27.69), as were those with CD4 count <200 cells/mm(3) compared to those with >500 cells/mm(3) (aOR 3.95, 95%CI 1.23-12.72).

CONCLUSION

Our study in HIV-infected children showed a high TB case rate, a low rate of definite TB and a high rate of drug-resistant TB based on World Health Organization case definitions. Increased uptake of available TB tests and availability of new diagnostic tests remains a priority in high TB-HIV burden settings.

Intestinal polyparasitism in a rural Kenyan community

BACKGROUND

Polyparasitism seems to be a common feature in human populations in sub-Saharan Africa. However, very little is known about its epidemiological significance, its long term impact on human health or the types of interactions that occur between the different parasite species involved.

OBJECTIVES

To determine the prevalence and co-occurrence of intestinal parasites in a rural community in the Kibwezi, Makueni district, Kenya.

DESIGN

A cross sectional study.

SETTING

Kiteng'ei village, Kibwezi, Makueni district, between May and September 2006.

SUBJECTS

One thousand and forty five who comprised of 263 adult males, 271 adult females > 15 years of age and 232 boys, and 279 girls <15 years of age.

INTERVENTIONS

All infected members of the community were offered Praziquantel (at dosages of 40 mg/kg body weight) for Schistosomiasis and Albendazole (600 mg) for soil transmitted helminths.

RESULTS

A total of ten intestinal parasite species (five protozoan and five helminth parasite species) were present in this community and polyparasitsm was common in individuals 5-24 years of age with no gendar related differences. Most of the infections were mild. The protozoan parasites of public health significance present were Entamoeba histolytica and Giardia lamblia with prevalence of 12.6% and 4.2%, respectively. The helminth parasites of public health significance in the locality were Schistosoma mansoni with a prevalence of 28%, and hookworms prevalence of 10%. About 53% of the study population harboured intestinal parasite infections, with 31% of the infected population carrying single parasite species infections, and 22% harbouring two or more intestinal parasite species per individual. Significant positive associations (p values <0.05) were observed between S. mansoni and hookworms, hookworms and Hymenolepis. nana and Entamoeba histolytica and Entamoeba coli.

CONCLUSION

Intestinal polyparasitism was common in the Kiteng'ei community, particularly in individuals aged of 5-24 years old. An integrated control programme of approach would be recommended for the control of S. mansoni, hookworms and Entamoeba histolytica for this community.

Hepatosplenomegaly associated with chronic malaria exposure: evidence for a pro-inflammatory mechanism exacerbated by schistosomiasis

In sub-Saharan Africa, chronic hepatosplenomegaly, with palpable firm/hard organ consistency, is common, particularly among school-aged children. This morbidity can be caused by long-term exposure to malaria, or by Schistosoma mansoni, and it is exacerbated when these two occur together. Although immunological mechanisms probably underlie the pathogenic process, these mechanisms have not been identified, nor is it known whether the two parasites augment the same mechanisms or induce unrelated processes that nonetheless have additive or synergistic effects. Kenyan primary schoolchildren, living in a malaria/schistosomiasis co-transmission area, participated in cross-sectional parasitological and clinical studies in which circulating immune modulator levels were also measured. Plasma IL-12p70, sTNF-RII, IL-10 and IL-13 levels correlated with relative exposure to malaria, and with hepatosplenomegaly. Soluble-TNF-RII and IL-10 were higher in children infected withS. mansoniHepatosplenomegaly caused by chronic exposure to malaria was clearly associated with increased circulating levels of pro-inflammatory mediators, with higher levels of regulatory modulators, and with tissue repair cytokines, perhaps being required to control the inflammatory response. The higher levels of regulatory modulators amongstS. mansoniinfected children, compared to those without detectableS. mansoni and malarial infections, but exposed to malaria, suggest thatS. mansoniinfection may augment the underlying inflammatory reaction.

Hepatosplenic morbidity in two neighbouring communities in Uganda with high levels of Schistosoma mansoni infection but very different durations of residence

Peri-portal fibrosis can be a serious sequelae of Schistosoma mansoni infection. Age or duration of exposure have been identified as important risk factors, but their relative importance cannot be easily separated. Here, we have compared two cohorts, aged 6-50 years and resident for ten years or since birth, from two neighbouring villages (Booma and Bugoigo) on the eastern shore of Lake Albert, Uganda. Parasitological measurements were similar, whereas the prevalence of peri-portal fibrosis was 5-fold higher in Booma. Data from the cohorts were pooled to assess the relative contribution of age and duration of residency on the risk of disease. Amongst adults, duration of residency was the critical risk factor--individuals aged 17-31 years resident for more 22 years had an almost 12-fold increased risk of fibrosis than those resident for less than 15 years. Height-standardised Splenic Vein Diameter (SVD), Portal Vein Diameter (PVD), Para-sternal Liver Length (PLL) and Spleen Length (SL) values were all higher in Booma, and each organometric parameter except PLL increased with the severity of fibrosis. Our results clearly demonstrate that duration of exposure is a critical risk factor for the development of peri-portal fibrosis and its sequelae in adults. This parameter should therefore be a routine measurement during epidemiological surveys of S. mansoni.

Schistosoma haematobium-induced urinary tract morbidity correlates with increased tumor necrosis factor-alpha and diminished interleukin-10 production

This study examined the hypothesis that the nature of the host cellular immune response to schistosome ova is a risk factor for urinary tract morbidity in areas in which Schistosoma haematobium is endemic. S. haematobium-infected children and adolescents with bladder pathology assessed by ultrasonography had 54-fold greater tumor necrosis factor (TNF)-alpha production and a 120-fold greater ratio of TNF-alpha to interleukin (IL)-10 release by peripheral blood mononuclear cells in response to egg antigens, in comparison with control children and adolescents matched by age, sex, and infection severity. Mycobacterial antigens also stimulated 7-fold more TNF-alpha among subjects with bladder morbidity than in control subjects, which suggests an innate predisposition to enhanced TNF-alpha production. Levels of egg antigen-induced IL-4 and -5 and interferon-gamma were equivalent in subjects with and without bladder pathology. Thus, children and adolescents predisposed to increased TNF-alpha production to S. haematobium infection are more likely to develop an exaggerated granulomatous response to ova trapped in the bladder wall, with associated urinary tract pathology.

A school-based approach to the control of urinary schistosomiasis and intestinal helminth infections in children in Matuga, Kenya: impact of a two-year chemotherapy programme on prevalence and intensity of infections

A school- and chemotherapy-based urinary schistosomiasis and intestinal helminth infection control programme was conducted in Matuga Division, Kwale District, Coast Province with teachers taking care of diagnosis, treatment and health education. More than 12,000 children in 36 primary schools were included in the 2-year programme. Results for 20 evaluation schools are presented. Children with haematuria were treated with praziquantel (40 mg/kg) once a year. Within 2 years, the prevalence of haematuria in the schools was reduced from 28% (range 8-68%) to 11.4% (range 3-23%). More than 80% of the schoolchildren were infected with one or more intestinal helminths at baseline. After one year with levamisole mass chemotherapy, single dose (2.5 mg/kg) three times a year (once per school term), the prevalence of Ascaris infection was reduced by 83% from 18% to 3%, but there was no change in pretreatment prevalences of hookworm (57%) and Trichuris (56%) infections. In the second year of the programme, albendazole 600 mg once every six months was administered to the children in 10 randomly selected schools. This resulted in 52% and 23% reductions in prevalences of hookworm and Trichuris infections, respectively, in these schools and a reduction in mean intensity of infection of 52.8% and 50.3%, respectively.

Chemotherapy-based control of schistosomiasis haematobia. IV. Impact of repeated annual chemotherapy on prevalence and intensity of Schistosoma haematobium infection in an endemic area of Kenya

To determine the effect of repeated, annual, age-targeted therapy on prevalence and intensity of Schistosoma haematobium infection in an endemic area, we treated all available, infected, school-age children (n = 2, 493) in the Msambweni area of Coast Province, Kenya with a randomized protocol of oral metrifonate (10 mg/kg for three doses each year) or praziquantel therapy (40 mg/kg as a single dose each year) for a period of one to three years. During 1984-1987, 1, 101 children completed three years of therapy, 550 received two years, and 842 received a single year. Annual followup revealed significant long-term suppression of S. haematobium infection in the targeted school-age population. Both cross-sectional analysis and study of individual outcomes suggested maximal suppression of infection after two years of therapy. Suppression lasted more than two years after cessation of treatment, and was associated with reduced community transmission (gauged by decreased prevalence among new study entrants and decreasing negative-to-positive conversion on annual parasitologic examinations). Comparison of metrifonate and praziquantel outcomes indicated greater suppression of infection and longer infection-free intervals for some subgroups given praziquantel. We conclude that annual population-based therapy targeted to schoolchildren has direct and indirect beneficial effects for endemic communities. In some specific situations, repeat therapy may not suppress transmission, and reduced drug efficacy may be observed after one to three years, suggesting the need for additional non-drug control measures in highly endemic villages.