EPIDEMIOLOGICAL REPORT ON OUTBREAK INVESTIGATION OF AES/JE IN MUZAFFARPUR DISTRICT, BIHAR IN 2016

Dr. Ragini Mishra 1 and Dr. Navin Mishra 2 . State Epidemiologist, State Surveillance Unit, State Health Society, Bihar, (2) Asst. Prof. Dept. of Dentistry, IGIMS, Patna. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History


ISSN: 2320-5407
Int. J. Adv. Res. 6(3), 624-634 625 The present study was done to review and assess the situation of AES/JE outbreak in Muzaffarpur, to determine the causes of current outbreak, to conduct an epidemiological and also entomological survey in some of the affected areas of Muzaffarpur, to assess the environmental and sociological factors contributing to the abundance of JE vector, to assess the current situation by district wise analysis of AES/JE outbreak and to recommend remedial measures to overcome the current outbreak and prevent occurrence of outbreaks in future.

Methodology:-
This was a record based study where daily reports on AES cases in prescribed format was reported from district surveillance unit comprising of Govt Medical College & Hospitals to the State Surveillance Unit. Lab reports for JE IgM ELISA, Pyogenic Meningitis and Tubercular Meningitis were also collected for recording respective cases. WHO case definition was used for inclusion of cases. Descriptive epidemiology based on time, place and person was used to analyze the outbreak trend of AES. Entomological investigations consisted of adult and larval survey as per standard protocol. Water logged places and containers were searched for the presence of culex larvae in the affected villages. Larvae were collected with the help of dippers. Three dips per sq m of breeding habitat surface area were taken. Adults were collected by 2 methods viz: Oral Aspirator and torch method by which Per Man Hour Density (PMHD) was calculated both indoors and outdoors. Total catch of mosquitoes was also done to determine species composition and its vectorial capability. The samples were sent to NIMR Ranchi for this purpose. Environmental investigations were done as per pre-planned questionnaire. Discussion was held with the District authorities and medical and paramedical staff to know the background information of the affected areas, genesis of outbreak, investigations carried out so far and control measures undertaken. Discussion was held with the physicians who treated the cases about the clinical presentation of cases, results of laboratory investigations and outcome of cases. Interview and clinical examination of some of the cases were done. Visit to the affected areas for rapid fever survey by house to house visit and collection of sera samples from suspected cases for JE confirmatory test was done.

Site description/Muzaffarpur district profile:-
Muzaffarpur district of Bihar is spread over an area of 3172 sq. kms. The district is bounded on the north by East Champaran and Sitamarhi districts, on the south by the district of Vaishali, on the east by the districts of Darbhanga and Samastipur (part) and on the west by Saran and part of Gopalganj districts. Important rivers include Bagmati, Gandak, Burhi Gandak & Lakhandeye. Average rainfall is 1187 cm annually. The district has a population of 3.743 million (2001 census). Rural population in the district is 90.7% and urban population is 9.3%.The density of the population was 929 per sq. kms. Literacy rate is 95%. There are 2 Sub divisions, 16 Blocks, 387 Panchayats and 1811 villages. Agriculture is the main occupation in the district.

Results and Discussion:-General Observations:-
The team visited affected areas in village Bahbal Bazar (Minapur block), Jhapahan (Mushahari block) & Salempur (Minapur block) for detailed outbreak investigation. Water logged places and containers were searched for the presence of culex larvae in the affected villages. Most of the affected areas visited, were comprised of agricultural labour population. Agriculture and Live stock rearing including Piggery was a major source of livelihood in the affected areas that were visited. The JE cases that were met had been previously vaccinated. As per information from the villagers, the Pig farms were located within 1 Km of the residence of the affected JE cases. This is an important finding as the presence of culex mosquitoes in the affected areas and its flight range of 1-2 kms from the pig dwellings might have led to JE transmission. Majority of the population were illiterate and belonged to lower socio-economic strata.
Epidemiological results:-Overall 70 cases of AES were reported in Muzaffarpur till 16 July 2016. Out of 70 cases, 13 cases were confirmed to be Japanese Encephalitis while other 2 as pyogenic and tubercular meningitis. Most affected block was Mushahri (14 cases)>Minapur (10 cases).Approximately in all the cases, most common symptoms were fever, altered sensorium and seizures. Age group most affected was 0-4 (52%)>5-9 (41%). Males (54%) were more affected than females (46%).Outbreak peak laid from 1-10 June 16 when 27 cases and 2 deaths were reported. Out of the two fever samples tested for JE by State IDSP team in PMCH, Patna one sample was negative while other was equivocal with strong inclination towards positivity.

Environmental & Sociological Observations and Results:-
Most of the affected population belonged to low socio-economic strata, with most of the houses being semipucca/Kutcha category. Sanitation and hygiene in affected areas were also poor. Majority of them were illiterate and 629 unaware of the cause of the disease. Awareness regarding disease control & prevention was also very less. Piggeries were found within 1 Km range of the JE affected cases.  Entomological investigations revealed that PMHD of Culex was higher when compared to Anopheles favouring transmission of JE. Most common breeding sites for larvae were cattle feeding containers>household containers. As per informants of the affected areas, only focal spray/fogging was done in affected area once. Amplifying hosts, pigs were present near the JE affected areas. Most of the affected population belonged to low socio-economic strata, with most of the houses being semi-pucca/kutcha category. Sanitation and hygiene in affected areas were also poor. Majority of them were illiterate and unaware of the cause of the disease. Awareness regarding disease control & prevention was also very less. With the advent of monsoon season, water logging in various places including paddy field may further aggravate JE transmission if appropriate steps are not taken on regular basis. There is urgent need for fogging in JE affected areas at regular intervals. Intensive IEC activities and awareness creation among community through Health Workers should also be undertaken along with enhancing fever surveillance and it's reporting on daily basis for early identification of suspected cases for prompt treatment and control.