Cholera outbreak investigation, Bhadola, Delhi, India, April-May 2018

BACKGROUND

In the Gangetic plains of India, including Delhi, cholera is endemic. On 10 May 2018, staff at the north Delhi district surveillance unit identified a laboratory-confirmed cholera outbreak when five people tested positive for Vibrio cholerae O1 Ogawa serotype in Bhadola. We investigated to identify risk factors and recommend prevention measures.

METHODS

We defined a case as ≥3 loose stools within 24 h in a Bhadola resident during 1 April-29 May 2018. We searched for cases house-to-house. In a 1 : 1 unmatched case control study, a control was defined as an absence of loose stools in a Bhadola resident during 1 April-29 May 2018. We selected cases and controls randomly. We tested stool samples for Vibrio cholerae by culture. We tested drinking water for fecal contamination. Using multivariable logistic regression we calculated adjusted ORs (aORs) with 95% CIs.

RESULTS

We identified 129 cases; the median age was 14.5 y, 52% were females, 27% were hospitalized and there were no deaths. Symptoms were abdominal pain (54%), vomiting (44%) and fever (29%). Among 90 cases and controls, the odds of illness were higher for drinking untreated municipal water (aOR=2.3; 95% CI 1.0 to 6.2) and not knowing about diarrhea transmission (aOR=4.9; 95% CI 1.0 to 21.1). Of 12 stool samples, 6 (50%) tested positive for Vibrio cholerae O1 Ogawa serotype. Of 15 water samples, 8 (53%) showed growth of fecal coliforms.

CONCLUSIONS

This laboratory-confirmed cholera outbreak associated with drinking untreated municipal water and lack of knowledge of diarrhea transmission triggered public health action in Bhadola, Delhi.

Measles outbreak among children ≤15 years old, Jaintia Hills District, Meghalaya, India, 2017

Background

Of 1115 measles outbreaks during 2015 in India, 61,255 suspected measles cases were reported. In 2016, a measles outbreak was reported at East and West Jaintia Hills districts in Meghalaya State, India.

Objectives

The outbreak was investigated to describe the epidemiology, estimate vaccination coverage and vaccine effectiveness (VE), determine risk factors for the disease, and recommend control and prevention measures.

Methods

A measles case was defined as new-onset fever with maculopapular rash occurring between May 1, 2016, and January 21, 2017, in a resident of East and West Jaintia Hills. Cases were identified by active and passive surveillance. Serum and urine samples were collected from cases with laboratory diagnosis for confirmation. A retrospective cohort study was conducted to estimate vaccination coverage, VE, and risk factors for the disease.

Results

We identified 382 cases (51% female). The attack rate was 24% with three deaths. The case fatality rate was <1%. The median age was 4 years (range: 3 months-12 years). Among children 12-60 months, 128 (56%) received measles-containing-vaccine first-dose (MCV1), 85 (37%) received measles-containing-vaccine second-dose (MCV2), and 80 (35%) received Vitamin A. VE for MCV1 was 78% and for MCV2 94%. Being unvaccinated for MCV1 (relative risk [RR] = 9.7, 95% confidence interval [CI] = 4.6-20.5) and MCV2 (RR = 17.4, 95% CI = 4.3-69.4) were both strongly associated with illness.

Conclusions

Poor vaccination coverage led to the measles outbreak in East and West Jaintia Hills districts of Meghalaya. Strengthening the routine immunization systems and improving Vitamin A uptake is essential to prevent further outbreaks.

Outbreak investigation of foodborne illness among political rally attendees, Cuddalore, Tamil Nadu, India

In July 2015, we investigated a foodborne illness outbreak in Sithalikuppam and Verupachi villages, Cuddalore district, Tamil Nadu, among the political rally attendees to determine the risk factors for illness. We conducted a retrospective cohort study, calculated risk ratio for the food exposures, and cultured stool specimens. Of 55 rally attendees, we identified 36 (65%) case patients; 32 (89%) had diarrhea and 20 (56%) had vomiting. Median incubation period was 14 h. Eighty-nine percent (32/36) of those who ate lemon rice at dinner had illness compared to 21% (4/19) of those who did not (RR 4.2). Of the six nonattendees who ate leftovers on July 25, all ate only lemon rice and became ill. Stool cultures were negative for Salmonella, Shigella, and Vibrio species. Lemon rice was probably contaminated with enterotoxins such as from Bacillus cereus. Our findings highlighted need for community food safety education and importance of thorough outbreak investigations.

Disease surveillance during a large religious mass gathering in India: The Prayagraj Kumbh 2019 experience

•

At Kumbh Mela 2019, disease surveillance was established for 22 acute diseases and syndromes.

•

Among the reported illnesses, 95% were communicable diseases such as acute respiratory illness (35%), acute fever (28%), and skin infections (18%).

•

The incident command centre generated 12 early warning signals from indicator-based and event-based surveillance: acute diarrheal diseases (n = 8, 66%), vector-borne diseases (n = 2, 16%), vaccine-preventable disease (n = 1, 8%), and thermal event (n = 1, 8%).

•

There were two outbreaks (acute gastroenteritis and chickenpox) that were investigated and controlled.

•

Implementation of disease surveillance facilitated early outbreak detection and response.

Background

Mass gathering (MG) events are associated with public health risks. During the period January 14 to March 4, 2019, Kumbh Mela in Prayagraj, India was attended by an estimated 120 million visitors. An onsite disease surveillance was established to identify and respond to disease outbreaks.

Methods

A health coordination committee was established for planning. Disease surveillance was prioritized and risk assessment was done to identify diseases/conditions based on epidemic potential, severity of illness, and reporting requirement under the International Health Regulations (IHR) of 2005. A daily indicator and event-based disease surveillance was planned. The indicator-based surveillance (IBS) manually and electronically recorded data from patient hospital visits and collected MG area water testing data to assess trends. The event-based surveillance (EBS) helped identify outbreak signals based on pre-identified event triggers from the media, private health facilities, and the food safety department. Epidemic intelligence was used to analyse the data and events to detect signals, verify alerts, and initiate the response.

Results

At Kumbh Mela, disease surveillance was established for 22 acute diseases/syndromes. Sixty-five health facilities reported 156 154 illnesses (21% of a total 738 526 hospital encounters). Among the reported illnesses, 95% (n = 148 834) were communicable diseases such as acute respiratory illness (n = 52 504, 5%), acute fever (n = 41 957, 28%), and skin infections (n = 27 094, 18%). The remaining 5% (n = 7300) were non-communicable diseases (injuries n = 6601, 90%; hypothermia n = 224, 3%; burns n = 210, 3%). Water samples tested inadequate for residual chlorine in 20% of samples (102/521). The incident command centre generated 12 early warning signals from IBS and EBS: acute diarrheal disease (n = 8, 66%), vector-borne disease (n = 2, 16%), vaccine-preventable disease (n = 1, 8%), and thermal event (n = 1, 8%). There were two outbreaks (acute gastroenteritis and chickenpox) that were investigated and controlled.

Conclusions

This onsite disease surveillance imparted a public health legacy by successfully implementing an epidemic intelligence enabled system for early disease detection and response to monitor public health risks. Acute respiratory illnesses emerged as a leading cause of morbidity among visitors. Future MG events should include disease surveillance as part of planning and augment capacity for acute respiratory illness diagnosis and management.

Public health surveillance during Simhastha Kumbh, a religious mass gathering in Ujjain district, Madhya Pradesh, India, 2016

A daily surveillance for disease detection and response at the Simhastha Kumbh Mela, in Ujjain, Madhya Pradesh, April-May 2016, was established. Existing weekly reporting of the Integrated Disease Surveillance Programme (IDSP) was modified to report 17 diseases or events from 22 public hospitals and three private hospitals in Ujjain. Water samples were also tested for fecal contamination in areas reporting diarrhea. We identified 56,600 ill persons (92% from government hospitals and 8% from private hospitals): 33% had fever, 28% acute respiratory infection, and 26% acute diarrheal diseases. There were 15 deaths (12 injury and 3 drowning). We detected two diarrhea outbreaks (Mahakaal Zone with 9 cases and Dutta Akhara Zone with 42 cases). Among 26 water samples, eight showed fecal contamination. This was a large implementation of daily disease surveillance in a religious mass gathering in India by IDSP. We recommended laboratory confirmation for diseases and similar daily surveillance in future mass gatherings in India.

A cutaneous Anthrax outbreak in Koraput District of Odisha-India 2015

Background

Cutaneous anthrax in humans is associated with exposure to infected animals or animal products and has a case fatality rate of up to 20% if untreated. During May to June 2015, an outbreak of cutaneous anthrax was reported in Koraput district of Odisha, India, an area endemic for anthrax. We investigated the outbreak to identify risk factors and recommend control measures.

Method

We defined a cutaneous anthrax case as skin lesions (e.g., papule, vesicle or eschar) in a person residing in Koraput district with illness onset between February 1 and July 15, 2015. We established active surveillance through a house to house survey to ascertain additional cases and conducted a 1:2 unmatched case control study to identify modifiable risk factors. In case control study, we included cases with illness onset between May 1 and July 15, 2015. We defined controls as neighbours of case without skin lesions since last 3 months. Ulcer exudates and rolled over swabs from wounds were processed in Gram stain in the Koraput district headquarter hospital laboratory.

Result

We identified 81 cases (89% male; median age 38 years [range 5–75 years]) including 3 deaths (case fatality rate = 4%). Among 37 cases and 74 controls, illness was significantly associated with eating meat of ill cattle (OR: 14.5, 95% CI: 1.4–85.7) and with close handling of carcasses of ill animals such as burying, skinning, or chopping (OR: 342, 95% CI: 40.5–1901.8). Among 20 wound specimens collected, seven showed spore-forming, gram positive bacilli, with bamboo stick appearance suggestive of Bacillus anthracis.

Conclusion

Our investigation revealed significant associations between eating and handling of ill animals and presence of anthrax-like organisms in lesions. We immediately initiated livestock vaccination in the area, educated the community on safe handling practices and recommended continued regular anthrax animal vaccinations to prevent future outbreaks.

Emerging/re-emerging viral diseases & new viruses on the Indian horizon

Infectious diseases remain as the major causes of human and animal morbidity and mortality leading to significant healthcare expenditure in India. The country has experienced the outbreaks and epidemics of many infectious diseases. However, enormous successes have been obtained against the control of major epidemic diseases, such as malaria, plague, leprosy and cholera, in the past. The country's vast terrains of extreme geo-climatic differences and uneven population distribution present unique patterns of distribution of viral diseases. Dynamic interplays of biological, socio-cultural and ecological factors, together with novel aspects of human-animal interphase, pose additional challenges with respect to the emergence of infectious diseases. The important challenges faced in the control and prevention of emerging and re-emerging infectious diseases range from understanding the impact of factors that are necessary for the emergence, to development of strengthened surveillance systems that can mitigate human suffering and death. In this article, the major emerging and re-emerging viral infections of public health importance have been reviewed that have already been included in the Integrated Disease Surveillance Programme.

Identification of burden hotspots and risk factors for cholera in India: An observational study

Background

Even though cholera has existed for centuries and many parts of the country have sporadic, endemic and epidemic cholera, it is still an under-recognized health problem in India. A Cholera Expert Group in the country was established to gather evidence and to prepare a road map for control of cholera in India. This paper identifies cholera burden hotspots and factors associated with an increased risk of the disease.

Methodology/Principle findings

We acquired district level data on cholera case reports of 2010–2015 from the Integrated Disease Surveillance Program. Socioeconomic characteristics and coverage of water and sanitation was obtained from the 2011 census. Spatial analysis was performed to identify cholera hotspots, and a zero-inflated Poisson regression was employed to identify the factors associated with cholera and predicted case count in the district. 27,615 cholera cases were reported during the 6-year period. Twenty-four of 36 states of India reported cholera during these years, and 13 states were classified as endemic. Of 641 districts, 78 districts in 15 states were identified as “hotspots” based on the reported cases. On the other hand, 111 districts in nine states were identified as “hotspots” from model-based predicted number of cases. The risk for cholera in a district was negatively associated with the coverage of literate persons, households using treated water source and owning mobile telephone, and positively associated with the coverage of poor sanitation and drainage conditions and urbanization level in the district.

Conclusions/Significance

The study reaffirms that cholera continues to occur throughout a large part of India and identifies the burden hotspots and risk factors. Policymakers may use the findings of the article to develop a roadmap for prevention and control of cholera in India.