Epidemiological,clinical, and public health response characteristics of a large outbreak of diphtheria among the Rohingya population in Cox’s Bazar,Bangladesh, 2017 to 2019: A retrospective study

BackgroundUnrest in Myanmar in August 2017 resulted in the movement of over 700,000 Rohingya refugees to overcrowded camps in Cox’s Bazar, Bangladesh. A large outbreak of diphtheria subsequently began in this population.Methods and findingsData were collected during mass vaccination campaigns (MVCs), contact tracing activities, and from 9 Diphtheria Treatment Centers (DTCs) operated by national and international organizations. These data were used to describe the epidemiological and clinical features and the control measures to prevent transmission, during the first 2 years of the outbreak. Between November 10, 2017 and November 9, 2019, 7,064 cases were reported: 285 (4.0%) laboratory-confirmed, 3,610 (51.1%) probable, and 3,169 (44.9%) suspected cases. The crude attack rate was 51.5 cases per 10,000 person-years, and epidemic doubling time was 4.4 days (95% confidence interval [CI] 4.2–4.7) during the exponential growth phase. The median age was 10 years (range 0–85), and 3,126 (44.3%) were male. The typical symptoms were sore throat (93.5%), fever (86.0%), pseudomembrane (34.7%), and gross cervical lymphadenopathy (GCL; 30.6%). Diphtheria antitoxin (DAT) was administered to 1,062 (89.0%) out of 1,193 eligible patients, with adverse reactions following among 229 (21.6%). There were 45 deaths (case fatality ratio [CFR] 0.6%). Household contacts for 5,702 (80.7%) of 7,064 cases were successfully traced. A total of 41,452 contacts were identified, of whom 40,364 (97.4%) consented to begin chemoprophylaxis; adherence was 55.0% (N = 22,218) at 3-day follow-up. Unvaccinated household contacts were vaccinated with 3 doses (with 4-week interval), while a booster dose was administered if the primary vaccination schedule had been completed. The proportion of contacts vaccinated was 64.7% overall. Three MVC rounds were conducted, with administrative coverage varying between 88.5% and 110.4%. Pentavalent vaccine was administered to those aged 6 weeks to 6 years, while tetanus and diphtheria (Td) vaccine was administered to those aged 7 years and older. Lack of adequate diagnostic capacity to confirm cases was the main limitation, with a majority of cases unconfirmed and the proportion of true diphtheria cases unknown.ConclusionsTo our knowledge, this is the largest reported diphtheria outbreak in refugee settings. We observed that high population density, poor living conditions, and fast growth rate were associated with explosive expansion of the outbreak during the initial exponential growth phase. Three rounds of mass vaccinations targeting those aged 6 weeks to 14 years were associated with only modestly reduced transmission, and additional public health measures were necessary to end the outbreak. This outbreak has a long-lasting tail, with Rt oscillating at around 1 for an extended period. An adequate global DAT stockpile needs to be maintained. All populations must have access to health services and routine vaccination, and this access must be maintained during humanitarian crises.

Jonathan Polonsky and colleagues report on a diphtheria outbreak among Rohingya people in Cox’s Bazar, Bangladesh during 2017-19.     

Molecular determination of van genes among clinical isolates of enterococci at a hospital setting

Vancomycin-resistant enterococci (VRE) poses a formidable challenge to public health due to its inherent resistance to multiple antibiotics coupled with the ability to transfer genetic determinants to dangerous pathogens like Methicillin-resistant Staphylococcus aureus (MRSA). The purpose of this study was to investigate the incidence of vancomycin resistance in enterococci among clinical isolates at a tertiary care military hospital in the eastern region of Saudi Arabia and to detect van genes using multiplex-PCR. Overall, 246 isolates of enterococci were collected from various clinical specimens. The isolates were identified, and antimicrobial susceptibility testing was done using the Vitek 2 system. Multiplex PCR was performed on the VRE isolates, thus identified to determine the van genes harbored. A total of 15 VRE were identified, of which 14 (93.3%) were Enterococcus faecium, and 1(6.7%) was Enterococcus casseliflavus with intrinsic vanC resistance. Of the 14 vancomycin-resistant Enterococcus faecium, 8 (57.1%) harbored vanB genes, while 6 (42.8%) harbored vanA genes. All the VRE were susceptible to linezolid and tigecycline. Our study detected a low prevalence (6.1%) of VRE among clinical isolates of enterococci and that the vanB gene predominates in such strains. Susceptibility profiles indicated that linezolid and tigecycline are still effective against these multidrug-resistant pathogens. Pus specimens yielded the highest percentage (53.3%) of isolates from which VRE was obtained, and this finding is novel among studies done in Saudi Arabia.     

Ischemia reperfusion dysfunction changes model-estimated kinetics of myofilament interaction due to inotropic drugs in isolated hearts

Background  

The phase-space relationship between simultaneously measured myoplasmic [Ca²⁺] and isovolumetric left ventricular pressure (LVP) in guinea pig intact hearts is altered by ischemic and inotropic interventions. Our objective was to mathematically model this phase-space relationship between [Ca²⁺] and LVP with a focus on the changes in cross-bridge kinetics and myofilament Ca²⁺ sensitivity responsible for alterations in Ca²⁺-contraction coupling due to inotropic drugs in the presence and absence of ischemia reperfusion (IR) injury.