Surveillance of Invasive Bacterial Diseases in Bangladesh

Funded by WHO | 2009-2015

What?

Considering the need of surveillance for invasive bacterial diseases, with specific attention to vaccine preventable diseases, we are conducting surveillance in 4 hospital and 1 rural field site of Bangladesh to provide information on invasive disease burden among under 5 children, to generate data on the most common serotypes causing disease and antimicrobial resistance patterns and to establish population-based incidence of laboratory-confirmed invasive bacterial diseases.

Why?

Invasive Bacterial diseases (IBD) in children <5 years is widely recognized as a priority public health problem with significant morbidity and mortality especially in the developing part of the world. Most of the complications and deaths are associated with pneumonia, sepsis and meningitis . While infrequently leading to death, other invasive bacterial diseases like typhoid and para-typhoid fever are also responsible for substantial morbidity of children.

Pneumonia is the leading cause of death among the children younger than 5 years which globally account to 19% under-5 mortality each year. Data on the pathogen-specific causes of pneumonia are limited, and available information is often difficult to interpret. Worldwide, without epidemics 1 million cases of bacterial meningitis are estimated to occur, 20% of which die annually and up to 54% of survivors are left with disability. Streptococcus pneumoniae and Haemophilus influenzae type-b is the leading pathogen causing pneumonia and meningitis, with high case fatality rate. Neisseria meningitidis (Meningococcus) which is responsible for meningitis can cause highest incidence of meningococcal diseases in the meningitis belt of Sub-Saharan Africa and during the epidemics. Typhoid fever is a systemic infection caused by Salmonella enterica serotype Typhi (S. typhi). The disease remains an important public health problem in developing countries estimating 16 million cases with 600,000 related deaths worldwide. S. typhi was the most common bacteria identified in culture and accounted for an estimated 211 hospitalization per 100,000 children < 5 years of age.

Culture of sterile fluids like blood and CSF are essential to diagnose any of these diseases they are not collected routinely ini developing countries like Bangladesh. So, the aetiology of IBD and their importance are not well recognized in these parts of the world. However, it is known that most of the 9 million child deaths are occurring in developing countries and a vast majority of them can be prevented by available vaccines. The scarcity of data on vaccine preventable diseases is hindering the evidence based decisions on introduction of vaccines in the developing countries including Bangladesh. To remove the barrier, specifically for invasive bacterial diseases, we are conducting surveillance in Bangladesh in a network of 4 hospitals since 2009.  Population-based incidence data for invasive bacterial diseases in Asia are extremely hard to come by. Incidence data could contribute to local and regional demand for prevention.  In poor settings like Bangladesh, exceedingly compelling information will be required to influence the immunization strategies through evidence based decision. Without such evidence, it will be challenging for decision- makers to justify redirection of funds or modification of programs and apply extremely limited resources toward bacterial prevention. From this surveillance, we will estimate population-based incidence of laboratory-confirmed invasive bacterial disease (IBD).

How?

We are continuing the surveillance at previously established network of two hospitals in Dhaka, one children’s hospital in Chittagong, second largest city in Bangladesh, and one hospital in Mirzapur serving a rural population of 400,000 people.  The hospitals are diverse in location and the populations they serve.  Each hospital maintains a microbiology laboratory having the capacity to isolate and identify organisms eventually that verified by DSH. A study physician is maintaining the day to day liaison with clinicians at the hospital and encouraging as well as facilitating them to obtain a blood culture when children <5 years of age are hospitalized with signs and symptoms for pneumonia, severe pneumonia, meningitis or sepsis and a lumbar puncture for evaluation of cerebrospinal fluid (CSF), including culture.  Study physicians identifies children meeting case definitions upon admission, keeps record of outcome, complications, therapy, duration of hospitalization and assures that the clinician receives results from blood or CSF culture processing. We are also collecting information about pre-hospitalization antimicrobial therapy which will be helpful in interpreting negative blood and CSF cultures– by comparing isolation rates among pre-treated and untreated children; we will estimate undetected casesamong pre-treated children.  A periodic monitoring of quality control is placed in the laboratories, errors are reviewed and refresher training is reinforced on demand based.  We provide Drug susceptibility and serotypes result to physician for patient care and to policy makers for interventions respectively. We are doing serotype of all available culture negative & antigen positive pneumococcal cases by Multiplex PCR.  We also serotypes H. influenzae, N. meningitdis and S. typhi by agglutination test using specific antisera. We are continuing the surveillance at 4 unions (population 116,921 ) close to Kumudini Hospital in order to facilitate compliance with referral. The estimated annual birth cohort in the surveillance area is 2,389. Each VHW is responsible for a cluster of about 2,300 people divided into five blocks and they visits all registered under-5 children once a week to enquire about health. VHWs assess the child, if mother complains of fever, cough or difficult breathing, and classify the sickness as per set algorithm followed by referral to Kumudini Hospital. In the Hospital, study physician screen both the VHW referred and self referred children and enroll the eligible children in the study after collection of specimen (blood and/ or CSF). A result of blood culture and of drug susceptibility is provided to the doctors in the hospital who may modify therapy based on results. All information is recorded on a standardized case report form. Medical care will be provided without charge for children who will participate in the surveillance.

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