On 9 June 2006 the Pan American Health Organization (PAHO) presented the Minister of Health of Brazil with the International Elimination of Transmission of Chagas' Disease Certificate. This act was the culmination of an intensive process that began in 1991 with the Southern Cone Initiative, a joint agreement between the governments of Argentina, Bolivia, Brazil, Chile, Paraguay, Uruguay and Peru, to control Chagas' disease by the elimination of the main vector, Triatoma infestans. This initiative has been highly successful and the prevalence area of the vector diminished rapidly in the last years. As a consequence, the current seroprevalence in children aged between 0 and 5 years is of the order of 10−5, a clear indication that transmission, if it is occurring, is only accidental. In this review I calculate the basic reproduction number, R0, for Chagas' disease and demonstrate that its relatively low value (1·25) explains why vectorial transmission was interrupted relatively easily. In addition, I used a mathematical model to forecast how long the remaining cases of the disease, as well as the additional vertically transmitted cases will last.

We report a large foodborne outbreak due to group A streptococci (GAS), which caused acute tonsillo-pharyngitis in 200–250 patrons of a company canteen in Copenhagen, Denmark, in June 2006. A retrospective cohort study of canteen users showed that consumption of cold pasta was associated with an increased risk of illness (attack rate 68%, risk ratio 4·1, P<0·0001). Indistinguishable GAS strains (emm89, T-type 3/13/B3264) were cultured from three cases and a cook, who had prepared the pasta. To our knowledge, pasta has previously only twice been incriminated as the source of a GAS outbreak. Only six foodborne GAS outbreaks have been reported in Europe since 1970, four of them in Sweden or Denmark. This geographical clustering suggests that foodborne GAS outbreaks are probably under-recognized elsewhere.

In France, surveillance of anti-tuberculosis drug resistance is performed by the Azay-Mycobacteria network, representing 30% of all culture-positive cases. We sought to validate administrative and clinical data gathered by the network in 2004 and to produce corrected resistance rates accounting for the observed misclassification. We reviewed a 10% sample of patients' records diagnosed in 2004 and measured the agreement between controlled data and data collected by the network by using the kappa (κ) statistic. A re-sampling bootstrap-based method was used to investigate the impact of bias found on resistance rates. Most of data collected by the network, such as demographic data, and country of birth had an excellent agreement (κ>0·8) with controlled data. The concordance was good (κ>0·6) for HIV status and tuberculosis site. The only variable slightly discordant with controlled data was prior history of treatment (κ=0·52). However, after correcting crude resistance rates for the observed misclassification, all estimated rates were within confidence intervals based on reported rates. This validation study is in favour of a good quality of data produced by the network, even though corrected rates are slightly different from observed rates. Therefore, data collected through the network may be used for policy making and tuberculosis programme evaluation. However, improvement in data collection regarding prior history of treatment should be considered.

Newly developed interferon-gamma release assays have become commercially available to detect tuberculosis (TB) infection in adults. However, little is known about their performance in children. We compared test results between the QuantiFERON-TB® Gold test (QFT) and tuberculin skin test (TST) in young children living with pulmonary TB patients in Cambodia. Of 195 children tested with both QFT and TST, the TST-positive rate of 24% was significantly higher than the QFT-positive rate of 17%. The agreement between the test results was considerable (κ-coefficient 0·63). Positive rates increased from 6% to 32% for QFT and from 15% to 43% for TST, according to the sputum smear grades of the index cases. The presence of Bacille Calmette-Guérin (BCG) scars did not significantly affect the results of TST or QFT in a logistic regression analysis. In conclusion, QFT can be a substitute for TST in detecting latent TB infection in childhood contacts aged ⩽5 years, especially in those who may have a false-positive TST due to BCG vaccination or non-tuberculous mycobacterial infection.

Rapidly growing mycobacteria (RGM) are environmental organisms that have emerged as significant human pathogens. RGM infections show remarkable geographic variations. In this study, based on data from Houston, Texas, RGM were isolated from clinical cultures year-round, although peaks in the summer and autumn correlating with the seasonal variation of temperature and rainfall also were noted. These results may offer some explanation for the summer occurrence of RGM outbreaks at diverse locations.

The first epidemic of sporotrichosis in humans as a result of zoonotic transmission was identified in Rio de Janeiro, Brazil, in 1998. A cross-sectional study was conducted applying questionnaires to patients seen in 2002 at Evandro Chagas Clinical Research Institute, Fiocruz, with a confirmed diagnosis of sporotrichsosis. A total of 73 dwellings were studied, where 255 individuals, including 94 patients and 161 healthy household contacts, lived with 133 cats with sporotrichosis. Most dwellings were houses with 83% having complete basic sanitation. Among patients, there was a predominance of women with a median age of 41 years who were engaged in domestic activities. These women contracted the disease twice more often than men. The prevalence of sporotrichosis was four times higher among patients caring for animals, irrespective of gender. In the current epidemic of sporotrichosis, taking care of sick cats was the main factor associated with transmission of the disease to humans.

The objective of the study was to identify the extent and cause of an outbreak of epidemic keratoconjunctivitis (EKC). The study design was active case finding and a case-control study of clinic patients who developed symptoms of EKC between 31 December 2005 and 31 March 2006. The main outcome measures were clinical procedures carried out and clinicians seen during clinic visit. Significantly more cases than controls had tonometry with instillation of anaesthetic drops (OR 16·5, 95% CI 3·9–145·1, P<0·01), optical coherence tomography (OR 4·7, 95% CI 1·2–21·9, P=0·01), or instillation of dilating drops by an orthoptist (OR 2·3, 95% CI 1·1–4·7, P=0·01). Significantly more cases than controls were seen by one orthoptist (OR 21·8, 95% CI 8·2–60·0, P<0·01). Transmission of EKC within the clinic was probably due to contamination of either or both the anaesthetic drops and the tonometer head in the room used by an orthoptist. A comprehensive suite of strategies is required to prevent healthcare-associated EKC.

We report on the first recorded outbreak of cholera in Namibia. From December 2006 to February 2007, more than 250 cases of cholera were reported from the Omusati and Kunene provinces of Namibia. However, only nine bacterial isolates were obtainable for analysis. Isolates were all identified as Vibrio cholerae O1 serotype Inaba biotype El Tor. All isolates were susceptible to ampicillin, augmentin, chloramphenicol, nalidixic acid, ciprofloxacin, tetracycline, kanamycin, imipenem, ceftriaxone and ceftazidime; and they all showed resistance to trimethoprim, sulfamethoxazole and streptomycin. Pulsed-field gel electrophoresis analysis of bacteria incorporating either SfiI or NotI digestion revealed an identical fingerprint pattern for all isolates. These data together with results indicating identical antimicrobial susceptibility profiles for all isolates determined that the outbreak was caused by a single strain of V. cholerae.

The fate of Salmonella enterica serovar Enteritidis (SE) in whole, unbroken eggs was monitored during storage at fixed or changing temperatures after inoculation with 20–47 c.f.u. of SE. Eggs stored at 10°C and 20°C showed little or no bacterial growth over 6 weeks, while egg storage at 30°C increased the percentage of the eggs that contained >106 c.f.u. after 3 weeks. Egg storage at 20°C for 5 days followed by 10°C caused only a few eggs with >106 c.f.u. after 2 weeks, whereas storage at 22–30°C or 27–35°C for 5 days followed by 25°C induced a rapid increase of eggs that contained >106 c.f.u. after 1 or 2 weeks, respectively. Therefore, egg storage at 10°C and 20°C can control SE growth, although the temperature during egg storage and transportation from farm to table should also be taken into consideration.

In France, salmonellosis is the main cause of foodborne bacterial infection with serotypes Enteritis (SE) and Typhimurium (ST) accounting for 70% of all cases. French authorities implemented a national control programme targeting SE and ST in poultry and eggs from October 1998 onwards. A 33% decrease in salmonellosis has been observed since implementation. We designed an evaluation of the impact of this control programme on SE and ST human infections in France. Using monthly Salmonella human isolate reports to the National Reference Centre we defined two intervention series (SE and ST) and one control series comprising serotypes not know to be associated with poultry or eggs. The series, from 1992 to 2003, were analysed using autoregressive moving average models (ARMA). To test the hypothesis of a reduction of SE and ST human cases >0 after the programme started and to estimate its size, we introduced an intervention model to the ARMA modelling. In contrast to the control series, we found an annual reduction of 555 (95% CI 148–964) SE and of 492 (95% CI 0–1092) ST human infections, representing respectively a 21% and 18% decrease. For SE, the decrease occurred sharply after implementation while for ST, it followed a progressive decrease that started early in 1998. Our study, suggests a true relation between the Salmonella control programme and the subsequent decrease observed for the two targeted serotypes. For ST, however, the decrease prior to the intervention may also reflect control measures implemented earlier by the cattle and milk industry.

We studied the role of host genetics in the susceptibility to severe Salmonella and Campylobacter infections and chronic sequelae of these infections. Participants of a previous case-control study were sent a buccal swab kit and a questionnaire about occurrence of chronic sequelae. Single nucleotide polymorphisms (SNPs) in the TLR4 (rs4986790), IFNG (rs2430561 and rs1861493), STAT1 (rs1914408), IL1B (rs16944), NRAMP (SLC11A1 rs2276631), JUN (rs11688) and VDR (rs10735810) genes were determined. In total, 687 controls, 457 Campylobacter cases and 193 Salmonella cases participated. None of the SNPs were associated with Campylobacter or Salmonella infections. None of the participants developed Guillain–Barré, Miller–Fisher or Reiter's syndrome. Reactive arthritis occurred in 5% and 2% of cases and controls, respectively. Campylobacter cases more frequently experienced gastroenteritis episodes than controls. Campylobacter or Salmonella infection in women, use of proton pump inhibitors and an SNP in the IFNG gene were independent risk factors for reactive arthritis. Another SNP in the IFNG gene and use of proton pump inhibitors were risk factors for recurrent episodes of gastroenteritis. In conclusion, reactive arthritis and recurrent gastroenteritis episodes are common after infection and host genetic factors play a role in susceptibility to these long-term health effects.

The prevalence of Salmonella in four layer farms in eastern Japan was investigated between 2004 and 2006 to determine the role of roof rats (Rattus rattus) in the epizootology of Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis). Persistent S. Enteritidis and S. Infantis contamination of the environment and pooled egg samples were detected in three out of four layer farms. A total of 113 (13·3%) and 158 (18·6%) out of 851 rats examined were positive for S. Enteritidis and S. Infantis, respectively. By pulsed-field gel electrophoresis, only one indistinguishable pulsed-field pattern was yielded by S. Enteritidis strains from rats, eggs and environmental samples from each of the two contaminated layer farms. Although, a variety of pulsed-field patterns were generated by S. Enteritidis isolates from rats, eggs, and the environment of the other contaminated farms, there are, however, some S. Enteritidis strains that are closely related clones. These results suggest that roof rats are carriers of S. Enteritidis and S. Infantis and that persistent S. Enteritidis and S. Infantis infections in a rat population may play an important role in the spread and maintenance of these pathogens inside the layer premises.

During the southern hemisphere winter of 2006 New Zealand experienced a significant increase in the number of reported cases of Campylobacter infection. In total, 112 Campylobacter isolates from eight district health boards (DHBs) located across New Zealand were submitted for PFGE, MLST and Penner serotyping analysis. Distinct clusters of Campylobacter isolates were identified, several of which were composed of isolates from up to five different DHBs located on both the North and South islands of New Zealand. One sequence type, ST-474, was identified in 32 of the 112 isolates and may represent an endemic sequence type present in New Zealand. The spatial pattern of genotypes, combined with the generalized increase in notifications throughout the country is consistent with a common source epidemic, most likely from a source contaminated with the dominant sequence types ST-474 and ST-190 and may also represent widely distributed stable clones present in New Zealand.

We describe a method of working on publicly available data to estimate disease prevalence in small geographic areas using Helicobacter pylori as a model infection. Using data from the Third National Health and Nutrition Examination Survey, risk parameters for H. pylori infection were obtained by logistic regression and validated by predicting 737·5 infections in an independent cohort with 736 observed infections. The prevalence of H. pylori infection in the San Francisco Bay Area was estimated with the probabilities obtained from a predictive logistic model, using risk parameters with individual-level 1990 U.S. Census data as input. Predicted H. pylori prevalence was also compared to gastric cancer incidence obtained from the Northern California Cancer Center and showed a positive correlation with gastric cancer incidence (P<0·001, R2=0·87), and no statistically significant association with other malignancies. By exclusively using publicly available data, these methods may be applied to selected conditions with strong demographic predictors.

Rift Valley fever virus (RVFV) is an arbovirus associated with periodic outbreaks, mostly on the African continent, of febrile disease accompanied by abortion in livestock, and a severe, fatal haemorrhagic syndrome in humans. However, the maintenance of the virus during the inter-epidemic period (IEP) when there is low or no disease activity detected in livestock or humans has not been determined. This study report prevalence of RVFV-neutralizing antibodies in sera (n=896) collected from 16 Kenyan wildlife species including at least 35% that were born during the 1999–2006 IEP. Specimens from seven species had detectable neutralizing antibodies against RVFV, including African buffalo, black rhino, lesser kudu, impala, African elephant, kongoni, and waterbuck. High RVFV antibody prevalence (>15%) was observed in black rhinos and ruminants (kudu, impala, buffalo, and waterbuck) with the highest titres (up to 1:1280) observed mostly in buffalo, including animals born during the IEP. All lions, giraffes, plains zebras, and warthogs tested were either negative or less than two animals in each species had low (⩽1:16) titres of RVFV antibodies. Of 249 sera collected from five wildlife species during the 2006–2007 outbreak, 16 out of 19 (84%) of the ruminant (gerenuk, waterbuck, and eland) specimens had RVFV-neutralizing titres ⩾1:80. These data provide evidence that wild ruminants are infected by RVFV but further studies are required to determine whether these animals play a role in the virus maintenance between outbreaks and virus amplification prior to a noticeable outbreak.

The KwaZulu Natal and Eastern Cape provinces of South Africa have experienced a serious dog rabies epidemic over the past three decades. Towards a better understanding of this epidemic, we have previously analysed nucleotide sequences of 142 rabies virus specimens that were obtained from these regions during 2003–2004 and provided a molecular description of the geographical distribution of rabies viral variants in the affected provinces. Here, as an extension, we studied five human cases that occurred during 2002–2003 and demonstrated the use of the sequence database in tracking unknown human rabies case histories. We were able to identify the geographical origin of viruses responsible for each human infection and in one case obtained evidence that suggested a non-bite transmission of rabies virus from an infected dog to a child. We argue for the value of this information in surveillance and epidemiological study and in the follow-up and management of potential exposures.

The recent epidemic of chikungunya fever (2005–2006) in India has affected millions of people. The Andaman and Nicobar Islands, an archipelago situated in the Bay of Bengal 1200 km from peninsular India, also witnessed an outbreak of chikungunya fever starting in July 2006 which affected thousands of people. Chikungunya fever classically manifests as high fever, myalgia, arthralgia and arthritis and in a certain percentage of cases with maculopapular rashes. However, deviation from the classical clinical features of chikungunya fever was reported in the earlier and recent epidemics. During the recent epidemic in the Andaman and Nicobar Islands we came across ten cases of flaccid limb weakness following symptoms and signs suggestive of chikungunya fever. In four subjects we confirmed the diagnosis of chikungunya virus infection by serological method (IgM ELISA method). This is the case report of those four subjects.

Attempts to explain the clear seasonality of rotavirus infections have been made by relating disease incidence to climate factors; however, few studies have disentangled the effects of weather from other factors that might cause seasonality. We investigated the relationships between hospital visits for rotavirus diarrhoea and temperature, humidity and river level, in Dhaka, Bangladesh, using time-series analysis adjusting for other confounding seasonal factors. There was strong evidence for an increase in rotavirus diarrhoea at high temperatures, by 40·2% for each 1°C increase above a threshold (29°C). Relative humidity had a linear inverse relationship with the number of cases of rotavirus diarrhoea. River level, above a threshold (4·8 m), was associated with an increase in cases of rotavirus diarrhoea, by 5·5% per 10-cm river-level rise. Our findings provide evidence that factors associated with high temperature, low humidity and high river-level increase the incidence of rotavirus diarrhoea in Dhaka.

This study examined the prevalence of HIV and other sexually transmitted infections (STIs) in pregnant women in Kinshasa, the Democratic Republic of the Congo (DRC). Between April and July 2004, antenatal attendees at two of the largest maternity clinics in Kinshasa were tested to identify HIV status, syphilis, Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG). HIV seroprevalence was 1·9% in 2082 women. With PCR techniques, CT and NG infections were also uncommon in the first 529 women (1·7% and 0·4%, respectively). No active syphilis infection case was identified by Treponema pallidum haemagglutination assay (TPHA) and rapid plasma reagin test (RPR). A woman's risk of HIV infection was significantly associated with her reporting a male partner having had other female sexual partners (OR 2·7, 95% CI 1·2–6·2). The continuing low seroprevalence of HIV in pregnant women from Kinshasa was confirmed. Understanding factors associated with this phenomenon could help prevent a future HIV epidemic in low HIV transmission areas in Africa.