Estimating the annual burden of tick-borne encephalitis to inform vaccination policy, Slovenia, 2009 to 2013.

With an annual incidence between 8 and 15 per 100,000 population in the period from 2009 to 2013, Slovenia has one of the highest notified incidences of tick-borne encephalitis (TBE) in Europe. TBE vaccination coverage remains at about 7.3%. To inform vaccination policy, we used surveillance data from 2009 to 2013 to calculate the overall and age- and sex-specific mean annual TBE incidence. We estimated disability-adjusted life years (DALYs) with 95% uncertainty intervals (UI), using the Burden of Communicable Diseases in Europe approach from the European Centre for Disease Prevention and Control. The mean annual incidence was 11.6 per 100,000 population, peaking in older age groups (50-74 years: 18.5/100,000) while relatively lower among children (5-14 years: 10.2/100,000). We estimated an overall 10.95 DALYs per 100,000 population per year (95% UI: 10.25-11.65). In contrast to the TBE incidence, the disease burden in children aged 5-14 years was higher than in adults aged 50-74 years: 17.31 (95% UI: 14.58-20.08) and 11.58 (95% UI: 10.25-12.91) DALYs per 100,000 stratum-specific population, respectively. In a limited resource setting where prioritisation of TBE vaccination strategies is required, vaccination programmes targeting children may have a higher impact on disease burden.

Complications of varicella after implementation of routine childhood varicella vaccination in Germany.

A country-wide sentinel surveillance system was initiated in Germany after implementation of routine varicella vaccination of children >11 months. Sentinel physicians report monthly the number of cases and of severe varicella complications (VC). Case-based questionnaires are completed for VC. We evaluated trend and clinical features of reported VC from April 2005 to March 2009. Reported VC decreased by 81%.

Implications of partial immunity on the prospects for tuberculosis control by post-exposure interventions.

One-third of the world population (approximately 2 billion individuals) is currently infected with Mycobacterium tuberculosis, the vast majority harboring a latent infection. As the risk of reactivation is around 10% in a lifetime, it follows that 200 million of these will eventually develop active pulmonary disease. Only therapeutic or post-exposure interventions can tame this vast reservoir of infection. Treatment of latent infections can reduce the risk of reactivation, and there is accumulating evidence that combination with post-exposure vaccines can reduce the risk of reinfection. Here we develop mathematical models to explore the potential of these post-exposure interventions to control tuberculosis on a global scale. Intensive programs targeting recent infections appear generally effective, but the benefit is potentially greater in intermediate prevalence scenarios. Extending these strategies to longer-term persistent infections appears more beneficial where prevalence is low. Finally, we consider that susceptibility to reinfection is altered by therapy, and explore its epidemiological consequences. When we assume that therapy reduces susceptibility to subsequent reinfection, catastrophic dynamics are observed. Thus, a bipolar outcome is obtained, where either small or large reductions in prevalence levels result, depending on the rate of detection and treatment of latent infections. By contrast, increased susceptibility after therapy may induce an increase in disease prevalence and does not lead to catastrophic dynamics. These potential outcomes are silent unless a widespread intervention is implemented.

Diagnostic value of endoscopy for the diagnosis of giardiasis and other intestinal diseases in patients with persistent diarrhea from tropical or subtropical areas.

OBJECTIVE: Upper endoscopy has been suggested as a valuable tool in the diagnosis of giardiasis. The aim of this study was to compare two methods based on endoscopy, i.e. microscopy of duodenal fluid and histology, with a fluorescent-antibody assay for the detection of Giardia lamblia cysts in stool specimens. The role of endoscopy in the identification of other causes of chronic diarrhea acquired during travel abroad was also evaluated. MATERIAL AND METHODS: Thirty-one patients (9 F, 22 M, median age 39 years, range 19-63 years) with persistent diarrhea after returning from tropical or subtropical areas agreed to undergo upper gastrointestinal endoscopy before and after treatment. Lower gastrointestinal endoscopy was subsequently performed. Three stool samples from each patient were examined using the direct fluorescent-antibody assay (DFA) for the detection of G. lamblia, and by routine methods for other protozoal and bacterial enteric pathogens. Each patient underwent upper endoscopy and biopsies and duodenal fluid samples were taken. In 12 patients a further lower endoscopy was performed. RESULTS: In 16 patients G. lamblia was detected in stool samples by DFA (relative sensitivity: 100%). Histology of duodenal biopsies and microscopy of duodenal fluids allowed diagnosis of giardiasis to be made in only 8, and 3 patients, respectively (relative sensitivities: 21% and 44%). Besides giardiasis, upper endoscopic examination revealed an alternative diagnosis (tropical sprue), whereas six additional diagnoses were made by colonoscopy. In six patients the cause of chronic diarrhea remained unclear. CONCLUSIONS: Compared to stool examinations using DFA, upper endoscopy is less sensitive for the diagnosis of giardiasis. In patients with negative stool examinations, lower endoscopy yields relevant diagnoses more often than upper endoscopy.

Major outbreak of hepatitis A associated with orange juice among tourists, Egypt, 2004.

In 2004, a major outbreak of hepatitis A among tourists returning from Egypt involved 351 case-patients from 9 European countries who were infected with a single strain (genotype 1 b). The case-control study identified orange juice as the most likely infection vehicle. Vaccination against hepatitis A virus is strongly recommended before travel to disease-endemic areas.

Identifying risk factors for tungiasis and heavy infestation in a resource-poor community in northeast Brazil.

Tungiasis is a neglected parasitic skin disease caused by penetration of female sand fleas into the epidermis. The ectoparasitosis is widespread in resource-poor communities in South America, the Caribbean and sub-Saharan Africa. To identify risk factors for the presence of sand fleas and severe infestation in an endemic community, we examined the entire population of a traditional fishing village for the presence of embedded sand fleas and determined the number and type of lesions. Demographic, behavioural and environmental characteristics of the population were assessed using a structured questionnaire. Multivariable analysis showed that both occurrence of tungiasis and heavy infestation were significantly related to poor housing conditions (odds ratio [OR]=4.7, 95% CI 1.4-15.8), lack of health education (OR=4.1, 95% CI 2.0-8.6) and presence of animals on the compound (OR=1.9, 95% CI 1.1-3.4). Contrary to common belief, a protective effect of frequent use of closed footwear could not be demonstrated. Based on the population attributable fractions calculated for the major risk factors identified, we conclude that several low-cost interventions would have a considerable impact on the occurrence of tungiasis and heavy infestation.

Selective mass treatment with ivermectin to control intestinal helminthiases and parasitic skin diseases in a severely affected population.

OBJECTIVE: To assess the short-term and long-term impact of selective mass treatment with ivermectin on the prevalence of intestinal helminthiases and parasitic skin diseases in an economically depressed community in north-east Brazil. METHODS: An intervention was carried out in a traditional fishing village in north-east Brazil where the population of 605 is heavily affected by ectoparasites and enteroparasites. The prevalence of intestinal helminths was determined by serial stool examination and the prevalence of parasitic skin diseases by clinical inspection. A total of 525 people out of a target population of 576 were treated at baseline. The majority of these were treated with ivermectin (200 microg/kg with a second dose given after 10 days). If ivermectin was contraindicated, participants were treated with albendazole or mebendazole for intestinal helminths or with topical deltamethrin for ectoparasites. Follow-up examinations were performed at 1 month and 9 months after treatment. FINDINGS: Prevalence rates of intestinal helminthiases before treatment and at 1 month and 9 months after mass treatment were: hookworm disease 28.5%, 16.4% and 7.7%; ascariasis 17.1%, 0.4% and 7.2%; trichuriasis 16.5%, 3.4% and 9.4%; strongyloidiasis 11.0%, 0.6% and 0.7%; and hymenolepiasis 0.6%; 0.4% and 0.5%, respectively. Prevalence rates of parasitic skin diseases before treatment and 1 month and 9 months after mass treatment were: active pediculosis 16.1%, 1.0% and 10.3%; scabies 3.8%, 1.0% and 1.5%; cutaneous larva migrans 0.7%, 0% and 0%; tungiasis 51.3%, 52.1% and 31.2%, respectively. Adverse events occurred in 9.4% of treatments. They were all of mild to moderate severity and were transient. CONCLUSION: Mass treatment with ivermectin was an effective and safe means of reducing the prevalence of most of the parasitic diseases prevalent in a poor community in north-east Brazil. The effects of treatment lasted for a prolonged period of time.

Malarone treatment failure not associated with previously described mutations in the cytochrome b gene.

Malarone (atovaquone-proguanil) is an effective drug for the treatment and prophylaxis of multidrug-resistant falciparum malaria. However, first cases of resistance have been reported, which are associated with mutations at codon 268 of the parasite's cytochrome b gene. We report the first case of Malarone treatment failure from Central Africa.Drug concentration was well within curative range. Pre- and post-treatment Plasmodium falciparum isolates revealed codon 268 wild-type alleles, and no other mutations of the putative atovaquone-binding domain.These findings illustrate the spread of atovaquone-proguanil-resistance in Africa and question the usefulness of codon 268 as the only target for the surveillance of its emergence.

Short communication: Prevalence of mutations associated with resistance to atovaquone and to the antifolate effect of proguanil in Plasmodium falciparum isolates from northern Ghana.

Atovaquone-proguanil has recently been introduced for the treatment and prophylaxis of malaria. However, resistance of Plasmodium falciparum is increasingly reported. We assessed P. falciparum polymorphisms associated with resistance to atovaquone (cytochrome b, cytb) and to cycloguanil, the active compound of proguanil (dihydrofolate reductase, dhfr) in 100 isolates from northern Ghana. None of these exhibited cytb codon 268 mutations. Moreover, no dhfr V16A, S108T or I164L mutations linked with cycloguanil resistance were detected. However, dhfr triple mutants (S108N-I51L-C59R) conferring resistance to proguanil and sulphadoxine-pyrimethamine were seen in 51% of the isolates. In northern Ghana, P. falciparum cytb codon 268 mutations associated with atovaquone resistance are absent. Although proguanil appears to act synergistically with atovaquone in a way different from its antifolate property, the abundance of dhfr polymorphisms will likely compromise the prevention of dissemination of atovaquone-resistant parasites once emerged.

Investigations on the biology, epidemiology, pathology and control of Tunga penetrans in Brazil. II. Prevalence, parasite load and topographic distribution of lesions in the population of a traditional fishing village.

Tungiasis is hyperendemic in many poor communities in Brazil and is associated with considerable morbidity. In order to understand the factors that determine the distribution of this ectoparasitosis in a rural community, an epidemiological study was carried out in a traditional fishing village in Ceará State, north-eastern Brazil. Based on active case detection and voluntary participation, 91% of the population (belonging to 95% of all families) was examined. Embedded fleas were looked for over all parts of the body, counted, and the lesions were staged. The overall prevalence of infestation was 51.3% (95% CI: 47.0-55.5). More males than females were infested (54.8% vs 48.3%); however, this difference was not statistically significant. Age-specific prevalence rates followed an S-shaped curve with peaks in children aged 5-9 years and people elder than 60 years. The parasite burden was high (range 1-145 lesions; arithmetic mean: 8.9) and particularly elevated in males, children <15 years and the elderly. The distribution of the parasite burden was uneven within the population with the majority of the lesions in a few individuals: the 23 subjects (8% of all infested) with severe infestation (>30 lesions) accounted for 1,366 of the 2,493 lesions (54.8%) documented. The study shows that tungiasis is a highly prevalent ectoparasitosis in this deprived community with a peculiar distribution of prevalence and parasite burden.