Assessing the performance of remotely-sensed flooding indicators and their potential contribution to early warning for leptospirosis in Cambodia

Remote sensing can contribute to early warning for diseases with environmental drivers, such as flooding for leptospirosis. In this study we assessed whether and which remotely-sensed flooding indicator could be used in Cambodia to study any disease for which flooding has already been identified as an important driver, using leptospirosis as a case study. The performance of six potential flooding indicators was assessed by ground truthing. The Modified Normalized Difference Water Index (MNDWI) was used to estimate the Risk Ratio (RR) of being infected by leptospirosis when exposed to floods it detected, in particular during the rainy season. Chi-square tests were also calculated. Another variable—the time elapsed since the first flooding of the year—was created using MNDWI values and was also included as explanatory variable in a generalized linear model (GLM) and in a boosted regression tree model (BRT) of leptospirosis infections, along with other explanatory variables. Interestingly, MNDWI thresholds for both detecting water and predicting the risk of leptospirosis seroconversion were independently evaluated at -0.3. Value of MNDWI greater than -0.3 was significantly related to leptospirosis infection (RR = 1.61 [1.10–1.52]; χ2 = 5.64, p-value = 0.02, especially during the rainy season (RR = 2.03 [1.25–3.28]; χ2 = 8.15, p-value = 0.004). Time since the first flooding of the year was a significant risk factor in our GLM model (p-value = 0.042). These results suggest that MNDWI may be useful as a risk indicator in an early warning remote sensing tool for flood-driven diseases like leptospirosis in South East Asia

Pulmonary melioidosis in CAMBODIA: a prospective study

<p>Abstract</p> <p>Background</p> <p>Melioidosis is a disease caused by <it>Burkholderia pseudomallei </it>and considered endemic in South-East Asia but remains poorly documented in Cambodia. We report the first series of hospitalized pulmonary melioidosis cases identified in Cambodia describing clinical characteristics and outcomes.</p> <p>Methods</p> <p>We characterized cases of acute lower respiratory infections (ALRI) that were identified through surveillance in two provincial hospitals. Severity was defined by systolic blood pressure, cardiac frequency, respiratory rate, oxygen saturation and body temperature. <it>B. pseudomallei </it>was detected in sputum or blood cultures and confirmed by API20NE gallery. We followed up these cases between 6 months and 2 years after hospital discharge to assess the cost-of-illness and long-term outcome.</p> <p>Results</p> <p>During April 2007 - January 2010, 39 ALRI cases had melioidosis, of which three aged ≤2 years; the median age was 46 years and 56.4% were males. A close contact with soil and water was identified in 30 patients (76.9%). Pneumonia was the main radiological feature (82.3%). Eleven patients were severe cases. Twenty-four (61.5%) patients died including 13 who died within 61 days after discharge. Of the deceased, 23 did not receive any antibiotics effective against <it>B. pseudomallei</it>. Effective drugs that were available did not include ceftazidime. Mean total illness-related costs was of US$65 (range$25-$5000). Almost two-thirds (61.5%) incurred debt and 28.2% sold land or other belongings to pay illness-related costs.</p> <p>Conclusions</p> <p>The observed high fatality rate is likely explained by the lack or limited access to efficient antibiotics and under-recognition of the disease among clinicians, which led to inappropriate therapy.</p

Correlation between antibiotic susceptibilities and genotypes in Neisseria gonorrhoeae from different geographical origins: determinants monitoring by real- time PCR as a complementary tool for surveillance

ABSTRACT Objective To determine in Neisseria gonorrhoeae (NG) isolates from different geographical areas whether monitoring of major determinants involved in chromosomal antimicrobial resistance correlated with phenotypes and could constitute complementary tools for surveillance. Methods Real-time multiplex PCR assays targeting penA, mtrR, penB, ponA, gyrA and parC determinants were applied to 169 NG extracts. Minimum inhibitory concentrations for penicillin and ciprofloxacin were determined by E tests, and b-lactamase production was analysed using nitrocefin discs

Aetiology of acute meningoencephalitis in Cambodian children, 2010–2013

Acute meningoencephalitis (AME) is associated with considerable morbidity and mortality in children in developing countries. Clinical specimens were collected from children presenting with AME at two Cambodian paediatric hospitals to determine the major aetiologies associated with AME in the country. Cerebrospinal fluid (CSF) and blood samples were screened by molecular and cell culture methods for a range of pathogens previously associated with AME in the region. CSF and serum (acute and convalescent) were screened for antibodies to arboviruses such as Japanese encephalitis virus (JEV), dengue virus (DENV), and chikungunya virus (CHIKV). From July 2010 through December 2013, 1160 children (one month to 15 years of age) presenting with AME to two major paediatric hospitals were enroled into the study. Pathogens associated with AME were identified using molecular diagnostics, cell culture and serology. According to a diagnostic algorithm, a confirmed or highly probable aetiologic agent was detected in 35.0% (n=406) of AME cases, with a further 9.2% (total: 44.2%, n=513) aetiologies defined as suspected. JEV (24.4%, n=283) was the most commonly identified pathogen followed by Orientia tsutsugamushi (4.7%, n=55), DENV (4.6%, n=53), enteroviruses (3.5%, n=41), CHIKV (2.0%, n=23) and Streptococcus pneumoniae (1.6%, n=19). The majority of aetiologies identified for paediatric AME in Cambodia were vaccine preventable and/or treatable with appropriate antimicrobials

CTX-M β-Lactamases in Escherichia coli from Community-acquired Urinary Tract Infections, Cambodia

The prevalence of CTX-M β-lactamases has reached a critical level, which highlights the need for study of their spread in developing countries

Evolutionary histories and antimicrobial resistance in Shigella flexneri and Shigella sonnei in Southeast Asia.

Funder: HCT is a Wellcome International Training Fellow (218726/Z/19/Z). SB is a Wellcome Senior Research Fellow (215515/Z/19/Z). DTP is a leadership fellow funded through the Oak Foundation.Conventional disease surveillance for shigellosis in developing country settings relies on serotyping and low-resolution molecular typing, which fails to contextualise the evolutionary history of the genus. Here, we interrogated a collection of 1,804 Shigella whole genome sequences from organisms isolated in four continental Southeast Asian countries (Thailand, Vietnam, Laos, and Cambodia) over three decades to characterise the evolution of both S. flexneri and S. sonnei. We show that S. sonnei and each major S. flexneri serotype are comprised of genetically diverse populations, the majority of which were likely introduced into Southeast Asia in the 1970s-1990s. Intranational and regional dissemination allowed widespread propagation of both species across the region. Our data indicate that the epidemiology of S. sonnei and the major S. flexneri serotypes were characterised by frequent clonal replacement events, coinciding with changing susceptibility patterns against contemporaneous antimicrobials. We conclude that adaptation to antimicrobial pressure was pivotal to the recent evolutionary trajectory of Shigella in Southeast Asia

Evolutionary histories and antimicrobial resistance in Shigella flexneri and Shigella sonnei in Southeast Asia.

Funder: HCT is a Wellcome International Training Fellow (218726/Z/19/Z). SB is a Wellcome Senior Research Fellow (215515/Z/19/Z). DTP is a leadership fellow funded through the Oak Foundation.Conventional disease surveillance for shigellosis in developing country settings relies on serotyping and low-resolution molecular typing, which fails to contextualise the evolutionary history of the genus. Here, we interrogated a collection of 1,804 Shigella whole genome sequences from organisms isolated in four continental Southeast Asian countries (Thailand, Vietnam, Laos, and Cambodia) over three decades to characterise the evolution of both S. flexneri and S. sonnei. We show that S. sonnei and each major S. flexneri serotype are comprised of genetically diverse populations, the majority of which were likely introduced into Southeast Asia in the 1970s-1990s. Intranational and regional dissemination allowed widespread propagation of both species across the region. Our data indicate that the epidemiology of S. sonnei and the major S. flexneri serotypes were characterised by frequent clonal replacement events, coinciding with changing susceptibility patterns against contemporaneous antimicrobials. We conclude that adaptation to antimicrobial pressure was pivotal to the recent evolutionary trajectory of Shigella in Southeast Asia