The longitudinal association of venue stability with consistent condom use among female sex workers in two Mexico-USA border cities.

We examined the relationship between venue stability and consistent condom use (CCU) among female sex workers who inject drugs (FSW-IDUs; n = 584) and were enrolled in a behavioural intervention in two Mexico-USA border cities. Using a generalized estimating equation approach stratified by client type and city, we found venue stability affected CCU. In Tijuana, operating primarily indoors was significantly associated with a four-fold increase in the odds of CCU among regular clients (odds ratio [OR]: 3.77, 95% confidence interval [CI]: 1.44, 9.89), and a seven-fold increase among casual clients (OR: 7.18, 95% CI: 2.32, 22.21), relative to FSW-IDUs spending equal time between indoor and outdoor sex work venues. In Ciudad Juarez, the trajectory of CCU increased over time and was highest among those operating primarily indoors. Results from this analysis highlight the importance of considering local mobility, including venue type and venue stability, as these characteristics jointly influence HIV risk behaviours.

Consequences of polyparasitism on anaemia among primary school children in Zimbabwe.

The effect of concomitant infection with schistosomes, Plasmodium falciparum and soil transmitted helminths (STHs) on anaemia was determined in 609 Zimbabwean primary school children. P. falciparum, haemoglobin levels and serum ferritin were determined from venous blood. Kato Katz, formal ether concentration and urine filtration techniques were used to assess prevalence of Schistosoma mansoni, STHs and Schistosoma haematobium infections. The prevalence of S. haematobium, S. mansoni, P. falciparum, hookworm, Trichuris trichiura and Ascaris lumbricoides were 52.3%, 22.7%, 27.9%, 23.7%, 2.3% and 2.1%, respectively. The overall prevalence of anaemia and iron deficiency anaemia (IDA) were 48.4% (277/572) and 38.1% (181/475). Haemoglobin levels among children who had P. falciparum, S. haematobium and hookworm were lower than negative individuals, p<0.001, p<0.001 and p=0.030, respectively. The prevalence of anaemia and IDA in co-infections was almost double that in single infection. Children with P. falciparum/STHs/schistosome and schistosomes/P. falciparum co-infections recorded higher prevalence of anaemia and IDA (80.8% and 57.4%, respectively) than other combinations, p<0.001. Logistic regression revealed that, age group > or = 14 years, P. falciparum, S. haematobium light and heavy infections, and S. mansoni moderate and heavy infection, hookworm light infection were predictors of anaemia. This study suggests that integrated school based de-worming and malaria control have the potential to reduce the burden of anaemia.

Deportation along the U.S.-Mexico border: its relation to drug use patterns and accessing care.

Since migration has been linked to new drug trends and risky behaviors, and deported individuals face unique economic and social stressors, we investigated behaviors of injection drug users (IDUs) from Tijuana, Mexico in relation to deportation history. In 2005, IDUs > or =18 years old who injected within the prior month were recruited by respondent-driven sampling, administered a questionnaire, and underwent antibody testing for HIV, HCV, and syphilis. Logistic regression compared IDUs who reported coming to Tijuana due to deportation from the U.S. versus others in the study. Of 219 participants, 16% were deportees. Prevalence of HIV, HCV and syphilis was 3, 95 and 13%, respectively. Deportees had lived in Tijuana for a shorter time (median: 2 vs. 16 years), were more likely to inject multiple times/day (OR: 5.52; 95%CI: 1.62-18.8), but less likely to have smoked/inhaled methamphetamine (OR: 0.17; 95%CI: 0.17-0.86). Deportation history was inversely associated with receiving drug treatment (OR: 0.41; 95%CI: 0.19-0.89), recent medical care (OR: 0.37; 95%CI: 0.13-1.00), or HIV testing (OR: 0.44; 95%CI: 0.19-1.02). Deportees had different drug use patterns and less interaction with public health services than other study participants. Our study is an indication that migration history might relate to current risk behaviors and access to health care. More in-depth studies to determine factors driving such behaviors are needed.

The burden of polyparasitism among primary schoolchildren in rural and farming areas in Zimbabwe.

A cross-sectional study was conducted in Zimbabwe among 1303 primary schoolchildren from a rural (53.3%) and a commercial farming area (46.7%) to determine the prevalence of co-infection by helminths and Plasmodium falciparum. Urine was examined on three successive days using the filtration method. Two stool specimens were processed using the Kato-Katz method and a third specimen was processed using the sedimentation method. Plasmodium falciparum was diagnosed from thick blood films. The prevalence of Schistosoma haematobium in the rural and farming areas was 66.8% and 52.3%, respectively, and for S. mansoni the prevalence was 12.4% and 22.7%, respectively. Plasmodium falciparum, hookworms, Ascaris lumbricoides and Trichuris trichiura occurred only in the farming area, with a prevalence of 27.9%, 23.7%, 2.1%, 2.3%, respectively. Co-infection and triple infection with schistosomes, P. falciparum and soil-transmitted helminths occurred in the commercial farming area only. Hookworm and S. mansoni infections were associated with P. falciparum malaria (P<0.001, OR=2.48, 95% CI 1.56-3.93 and P=0.005, OR=1.85, 95% CI 1.20-2.87, respectively). Overlap of helminths with malaria is a concern among primary schoolchildren and incorporating helminth control in programmes aiming to control malaria will improve funding and increase the efficiency of control for neglected tropical diseases in identified co-endemic settings.

Efficacy and side effects of praziquantel treatment against Schistosoma haematobium infection among primary school children in Zimbabwe.

We examined the efficacy of praziquantel against Schistosoma haematobium among primary school children during a school-based deworming programme in the Burma Valley commercial farming area and the Nyamaropa rural areas in Zimbabwe, where the disease is highly endemic. Among 767 individuals infected with S. haematobium, 675 (88.0%) received treatment. Two single oral doses of 40mg/kg praziquantel were given 6 weeks apart. Of the 675 participants, heavy infection intensity was more common in males than females (chi(2)=6.61, P=0.010). Six weeks later, 624 participants (92.4%) were successfully followed up. The overall cure rate was 88.5% and the egg reduction rate was 98.2%. The highest cure rate was among those individuals with light infection. Seventy-two individuals remained infected at 6 weeks post treatment, among which 3 and 69 individuals had heavy and light infection, respectively. Forty-six of these children resolved following a second round of treatment at 6 weeks follow-up. Of the remaining children successfully followed-up, 22 resolved after a third round of treatment 6 months later. A wide range of observed mild and transient side effects were not associated with egg intensity. The parasitological cure rate was not associated with gender or age. Our study demonstrates that praziquantel is efficacious against S. haematobium in Zimbabwe, although low levels of persistent infection warrant further investigation.

First molecular surveillance report of HIV type 1 in injecting drug users and female sex workers along the U.S.-Mexico border.

HIV prevalence is increasing among high-risk populations in the Mexican-U.S. border cities of Tijuana and Ciudad Juarez. In 2005, the molecular epidemiology of HIV-1 was studied among injecting drug users (IDU) and female sex workers (FSW) in these cities, which are corridors for over two-thirds of the migrant flow between Mexico and the United States. Eleven samples (eight IDU and three FSW) were successfully amplified, sequenced, and analyzed. The results revealed that all 11 samples were subtype B. There was no phylogenetic clustering or separation of the strains between IDU and FSW or between Tijuana and Ciudad Juarez nor was the Mexican strain phylogenetically distinct from other subtype B strains. Two of three drug naive FSWs had low-level HIV-1 resistance mutations. This community-based study demonstrated that HIV-positive IDUs and FSWs in Ciudad Juarez and Tijuana were predominantly infected with subtype B. Further prevalence studies on HIV-1 resistance mutations among FSWs in these border cities are warranted.

Genetic diversity of a population of Schistosoma haematobium derived from schoolchildren in east central Zimbabwe.

To characterize the extent of genetic diversity of Schistosoma haematobium within and among its definitive host (intra- and interhost parasite diversity), 133 individual isolates from 25 infected schoolchildren were compared using randomly amplified polymorphic DNA markers. With 4 primers, 53 unambiguous loci were identified, and of these, 22 were polymorphic. Mean heterozygosity in the population was 0.116 +/- 0.043. Analysis of molecular variance showed the majority of variance occurred within, rather than between, hosts. Frequencies of certain alleles segregated the parasite population into 13 distinct clusters of associated genotypes, with 4 of these first appearing 10 mo after the initial survey. Considering the level of diversity within this limited geographical area and the possibility of rapid turnover of genotypes, parasite variance may impact acquired immunity and clinical outcome of the infection.