Liana Ariza

A highly efficacious pediculicide based on dimeticone: Randomized observer blinded comparative trial

BackgroundInfestation with the human head louse (Pediculus humanus capitis) occurs worldwide. Existing treatment options are limited, and reports of resistance to commonly used pediculicides have been increasing. In this trial we assessed the efficacy of a product containing a high (92%) concentration of the silicone oil dimeticone (identical in composition to NYDA®), as compared to a 1% permethrin lotion.MethodsRandomized, controlled, observer blinded clinical trial. Participants were recruited from a poor urban neighbourhood in Brazil where pediculosis capitis was highly prevalent. To minimize reinfestation during the trial, participants (145 children aged 5–15 years with head lice infestations) were transferred to a holiday resort outside the endemic area for a period of 9 days. Two applications of dimeticone or 1% permethrin were done, seven days apart. Outcome measures were defined as cure (absence of vital head lice) after first application and before and after second applications, degree of itching, cosmetic acceptability, and clinical pathology.ResultsOverall cure rates were: day 2 – dimeticone 94.5% (95% CI: 86.6% – 98.5%) and permethrin 66.7% (95% CI: 54.6% – 77.3%; p < 0.0001); day 7 – dimeticone 64.4% (95% CI: 53.3% – 75.3%) and permethrin 59.7% (95% CI: 47.5% – 71.1%; p = 0.5); day 9 – dimeticone 97.2% (95% CI: 90.3% – 99.7%) and permethrin 67.6% (95% CI: 55.4%-78.2%); p < 0.0001). Itching was reduced similarly in both groups. Cosmetic acceptability was significantly better in the dimeticone group as compared to the permethrin group (p = 0.01). Two mild product-related incidents occurred in the dimeticone group.ConclusionThe dimeticone product is a safe and highly efficacious pediculicide. Due to its physical mode of action (interruption of the lices oxygen supply of the central nervous system), development of resistance is unlikely.Trial registrationCurrent Controlled Trials ISRCTN15117709.

Parasites of importance for human health in Nigerian dogs: high prevalence and limited knowledge of pet owners.

BackgroundDogs are the most common pet animals worldwide. They may harbour a wide range of parasites with zoonotic potential, thus causing a health risk to humans. In Nigeria, epidemiological knowledge on these parasites is limited.MethodsIn a community-based study, we examined 396 dogs in urban and rural areas of Ilorin (Kwara State, Central Nigeria) for ectoparasites and intestinal helminths. In addition, a questionnaire regarding knowledge and practices was applied to pet owners.ResultsNine ectoparasite species belonging to four taxa and six intestinal helminth species were identified: fleas (Ctenocephalides canis, Pulex irritans, Tunga penetrans), mites (Demodex canis, Otodectes sp., Sarcoptes scabiei var. canis), ticks (Rhipicephalus sanguineus, Ixodes sp.), and lice (Trichodectes canis); and Toxocara canis, Ancylostoma sp., Trichuris vulpis, Dipylidium caninum, Taenidae and Strongyloides sp. Overall prevalence of ectoparasites was 60.4% and of intestinal helminths 68.4%. The occurrence of C. canis, R. sanguineus, T. canis, Ancylostoma sp. and T. vulpis was most common (prevalence 14.4% to 41.7%). Prevalence patterns in helminths were age-dependent, with T. canis showing a decreasing prevalence with age of host, and a reverse trend in other parasite species. Knowledge regarding zoonoses was very limited and the diseases not considered a major health problem. Treatment with antiparasitic drugs was more frequent in urban areas.ConclusionParasites of importance for human health were highly prevalent in Nigerian dogs. Interventions should include health education provided to dog owners and the establishment of a program focusing on zoonotic diseases.

Prevalence and risk factors of toxoplasmosis among pregnant women in Fortaleza, Northeastern Brazil.

We determined the seroprevalence of Toxoplasma gondii and associated risk factors among 963 pregnant women attending an obstetric hospital in Fortaleza, Brazil. Seroprevalences of IgG and IgM against T. gondii were 68.6% (95% confidence interval [CI] = 65.6-71.6%) and 0.5% (95% CI = 0.06-1.0%), respectively. Seroprevalence of IgG was high in women less than 25 years of age (91.7%) and in low-income women (odds Ratio [OR] = 1.40, 95% CI = 1.02-1.90). Multivariate regression analysis showed that consumption of homemade water ice (adjusted OR = 1.49, 95% CI = 1.09-2.04), vegetables washed with untreated water (adjusted OR = 1.43, 95% CI = 1.05-1.94), consumption of chicken (adjusted OR = 1.49, 95% CI = 1.12-2.0), and dog ownership (adjusted OR= 1.46, 95% CI = 1.07-1.98) were factors associated with IgG seropositivity. Young women in northeastern Brazil living under poor socioeconomic conditions are at highest risk for acquiring infection with T. gondii. Oocyst contamination of water and soil must be addressed in future prevention strategies.

Risk Factors for Tungiasis in Nigeria: Identification of Targets for Effective Intervention

Background The parasitic skin disease tungiasis (caused by the flea Tunga penetrans) affects resource-poor communities in Latin America, the Caribbean and sub-Saharan Africa. Prevalences in endemic areas are high, and severe pathology occurs commonly. However, risk factors for infestation have never been assessed in Africa. Methods and Findings A cross-sectional study was conducted in Erekiti, a rural community in Lagos State (Nigeria), where tungiasis is endemic. Individuals were examined clinically for the presence of tungiasis, and a questionnaire was applied. Data from 643 individuals (86.6% of the target population) were analyzed; 252 (42.5%) were infested with T. penetrans. In the multivariate logistic regression analysis, presence of pigs on the compounds (adjusted odds ratio = 17.98; 95% confidence interval: 5.55–58.23), sand or clay floor inside houses (9.33; 5.06–17.19), and having the common resting place outside the house (7.14; 4.0–14.29) were the most important risk factors identified. The regular use of closed footwear (0.34; 0.18–0.62) and the use of insecticides indoors (0.2; 0.05–0.83) were protective against infestation. The population attributable fractions associated with tungiasis were: sand or clay floor inside the house (73.7%), resting usually outside the house (65.5%), no regular use of closed footwear (51.1%), and pigs on the compound (37.9%). Conclusion The presence of tungiasis in Erekiti is determined to an important extent by a limited number of modifiable variables. Effective and sustainable intervention measures addressing these factors need to be implemented in this and other West African communities with high disease burden.

Prevalence and risk factors of hookworm-related cutaneous larva migrans in a rural community in Brazil

Abstract The epidemiology of hookworm-related cutaneous larva migrans (HrCLM) in endemic communities is not well understood. To describe the prevalence of HrCLM and to identify environmental and behavioural risk factors for the infestation, two cross-sectional surveys were conducted in a small village in an endemic area of north–eastern Brazil — one in the rainy season and the other in the dry season. The members of each household were examined clinically for the presence of HrCLM, and information on possible risk factors was collected. HrCLM, which was diagnosed in 45 individuals in the rainy-season survey and in 17 in the dry-season survey, was significantly more prevalent in the rainy season (4.4% v. 1.7%; P<0.001). The age-specific prevalences peaked, at 14.9%, in infants and children aged ≤ 4 years. In a logistic regression analysis, the independent risk factors for current infestation or infestation in the preceding 6 months were identified as young age (odds ratio = 0.96; 95% confidence interval = 0.94–0.98), living in a house without a solid floor (odds ratio = 1.99; 95% confidence interval = 1.22–3.23), and walking barefoot (odds ratio = 1.77; 95% confidence interval = 1.12–2.80). In the study area, therefore, HrCLM is a common parasitic skin disease in children, is associated with behavioural and environmental risk factors, and shows marked seasonality in its prevalence. Local control of HrCLM should be based primarily on the health education of mothers and the elder girls who take care of their younger siblings.

Pigs are the most important animal reservoir for Tunga penetrans (jigger flea) in rural Nigeria

We examined the domestic animals and rodents in a community in rural Nigeria. Of the 133 animals examined, 29 (21.8%) were infested, the highest prevalence of infestation and highest parasite load was found in the pigs (prevalence 54.8%, median = nine embedded parasites), followed by dogs (45.5%; median = 4), Rattus rattus (29.4%; median = 2) and Mus minutoides (15.4%; median = 1.5). Of all the tungiasis lesions identified 83% were found in pigs. Our data confirm that tungiasis is a zoonotic disease, and that pigs are its most important animal reservoir in this endemic community.

The epidemiology of scabies in an impoverished community in rural Brazil: Presence and severity of disease are associated with poor living conditions and illiteracy

BACKGROUND We sought to study the epidemiology of scabies and to identify risk factors of severe disease in an impoverished rural community in northeast Brazil. METHODS The study was designed as a repeated cross-sectional study based on two door-to-door surveys. One survey was carried out in the rainy season, the other in the dry season. The inhabitants of the community were examined for the presence of scabies and demographic, socioeconomic, and behavioral risk factors were assessed. Risk factors were analyzed using bivariate and multivariate regression analysis. RESULTS The overall prevalence was 9.8% with no significant variation between seasons and the incidence was estimated to be 196/1000 person-years. The highest prevalence (18.2%) was observed in children younger than 4 years. Risk factors in the bivariate analysis were young age, presence of many children in the household, illiteracy, low family income, poor housing, sharing clothes and towels, and irregular use of shower. Age younger than 15 years, illiteracy, sharing of clothes, and living in the community for more than 6 months remained significant independent risk factors in multivariate regression analysis. LIMITATIONS We used a clinical case definition; specificity and sensitivity were not verified. Men were underrepresented in the study population. CONCLUSIONS In this impoverished community scabies is an important health problem characterized by continuous transmission throughout the year. The parasitic skin disease is embedded in a complex web of causation characterized by poor living conditions and a low level of education.

Interruption and defaulting of multidrug therapy against leprosy: population-based study in Brazil's Savannah Region.

Background Low adherence to multidrug therapy against leprosy (MDT) is still an important obstacle of disease control, and may lead to remaining sources of infection, incomplete cure, irreversible complications, and multidrug resistance. Methodology/Principal Finding We performed a population-based study in 78 municipalities in Tocantins State, central Brazil, and applied structured questionnaires on leprosy-affected individuals. We used two outcomes for assessment of risk factors: defaulting (not presenting to health care center for supervised treatment for >12 months); and interruption of MDT. In total, 28/936 (3.0%) patients defaulted, and 147/806 (18.2%) interrupted MDT. Defaulting was significantly associated with: low number of rooms per household (OR = 3.43; 0.98–9.69; p = 0.03); moving to another residence after diagnosis (OR = 2.90; 0.95–5.28; p = 0.04); and low family income (OR = 2.42; 1.02–5.63: p = 0.04). Interruption of treatment was associated with: low number of rooms per household (OR = 1.95; 0.98–3.70; p = 0.04); difficulty in swallowing MDT drugs (OR = 1.66; 1.03–2.63; p = 0.02); temporal non-availability of MDT at the health center (OR = 1.67; 1.11–2.46; p = 0.01); and moving to another residence (OR = 1.58; 95% confidence interval: 1.03–2.40; p = 0.03). Logistic regression identified temporal non-availability of MDT as an independent risk factor for treatment interruption (adjusted OR = 1.56; 1.05–2.33; p = 0.03), and residence size as a protective factor (adjusted OR = 0.89 per additional number of rooms; 0.80–0.99; p = 0.03). Residence size was also independently associated with defaulting (adjusted OR = 0.67; 0.52–0.88; p = 0.003). Conclusions Defaulting and interruption of MDT are associated with some poverty-related variables such as family income, household size, and migration. Intermittent problems of drug supply need to be resolved, mainly on the municipality level. MDT producers should consider oral drug formulations that may be more easily accepted by patients. Thus, an integrated approach is needed for further improving control, focusing on vulnerable population groups and the local health system.

Tungiasis: a neglected disease causing severe morbidity in a shantytown in Fortaleza, State of Ceará

The parasitic skin disease tungiasis, caused by the jigger flea Tunga penetrans, is endemic in low-income communities in Brazil. In this study, inhabitants of a shantytown in Fortaleza, northeastern Brazil, who had an elevated parasite load, were identified. The number of lesions, localization, staging and associated diseases were recorded. The 142 individuals identified were living in extremely precarious housing conditions. A total of 3,445 lesions located on the feet were counted (median = 17 lesions; maximum = 98 lesions). Almost without exception, the individuals had nail deformation and edema, and more than 70% presented with pain and fissures. There was nail loss in 46%; deformation of the digits in 25%; abscesses in 42%; and complaints of walking difficulty in 59%. Our data show that tungiasis in this low-income urban community typical of northeastern Brazil was associated with severe morbidity. Tungiasis needs to be recognized as a public health problem in this study area and other similar endemic areas.

A simple approach improving the performance of urine reagent strips for rapid diagnosis of urinary schistosomiasis in Nigerian schoolchildren.

In Nigeria, schistosomiasis, caused predominantly by the species Schistosoma haematobium, is highly endemic in resource-poor communities. We performed a school-based survey in two rural communities in Osun State (Southwestern Nigeria) and assessed macrohaematuria, microhaematuria and proteinuria as indirect indicators for the presence of disease. Urine samples were inspected macroscopically for haematuria and screened for microhaematuria and proteinuria using urine reagent strips. The microscopic examination of schistosome eggs was used as the gold standard for diagnosis. In total, 447 schoolchildren were included in this study and had a 51% prevalence of urinary schistosomiasis. The sensitivity of microhaematuria (68%) and proteinuria (53%) for infection with S. haematobium was relatively low. In patients with a heavy infection (>or= 500 eggs/10 mL), the sensitivity of microhaematuria was high (95%). When the presence of macrohaematuria and the concomitant presence of microhaematuria and proteinuria were combined, it revealed a sensitivity of 63%, a specificity of 93% and a positive predictive value of 91%. Macrohaematuria also showed high specificity (96%) and a positive predictive value of 92%, while sensitivity was < 50%. These data show that combining urine reagent strip tests (presence of proteinuria and microhaematuria) and information on macrohaematuria increased the accuracy of the rapid diagnosis of urinary schistosomiasis in an endemic rural West African setting. This simple approach can be used to increase the quality of monitoring of schistosomiasis in schoolchildren.