Is your drinking water safe? A rotavirus outbreak linked to water refilling stations in the Philippines, 2016

Introduction: In April 2016, the Department of Health in Zamboanga Peninsula reported an increase in the number of acute gastroenteritis cases reported from Zamboanga City. An epidemiologic investigation was conducted to verify the existence of an outbreak, determine source/mode of transmission and recommend control measures. Methods: A line list of cases was compiled from the 11 hospitals within Zamboanga City and a case-series study was conducted. Suspected cases were any persons from Zamboanga City who had three or more episodes of acute diarrhoea within 24 hours from 15 March to 29 May 2016. Confirmed cases were suspected cases with active symptoms during the investigation who had a stool sample collected with rotavirus detected. Water samples were also collected for viral detection. Results: There were 2936 suspected cases with 22 deaths (case fatality rate: 0.75%), an age range of 8 days to 89 years (median: 2 years), with those aged less than 5 years the most affected age group (1903/2936, 65%). The majority were males (1549/2936, 53%). From the 138 active case patients included in the case-series study, the majority reported contact with a family member who had diarrhoea (89/138, 64%) and using water refilling stations as their major source of drinking water (88/134, 64%). Of the 93 stool specimens collected, 56 (60%) were positive for rotavirus. Five samples from water refilling stations where case patients reported collecting drinking water were all positive for rotavirus. Discussion: Strict regulation of water refilling stations and boiling drinking water in households were implemented, immediately controlling the outbreak. After complying with all the requirements set by the Department of Health, a water safety certificate was awarded to Zamboanga City in September 2018

An assessment of disaster-related mortality post-Haiyan in Tacloban City

Introduction: Tacloban City was seriously affected by Typhoon Haiyan with 2321 deaths distributed across its 138 villages and subvillages. In January 2014, a team from the Department of Health conducted a mortality assessment to identify risk factors for deaths that occurred during Typhoon Haiyan. Methods: A retrospective case-control study was conducted in the four coastal villages in Tacloban City with the highest numbers of typhoon-associated deaths. A case was defined as a person who died in Tacloban City during Typhoon Haiyan and whose body was recovered and identified. Controls were selected from surviving family members. Information about typhoon-related knowledge, attitudes and practices of the cases was collected using a standardized questionnaire. Results: There were 100 cases and 100 controls included in the study. The cause of death for all cases was drowning, and all bodies were found inside or near their house. Multivariate analysis identified that the significant risk factors for mortality due to Haiyan were not evacuating before the storm hit (odds ratio [OR] = 10.0; 95% confidence interval [CI]: 3.8–29.1) and exiting their house during the storm (OR = 3.6; 95% CI: 1.9–7.1). Proxies reported that all cases had heard about the coming typhoon, but that 88% did not understand the message about the storm surge. Ninety-five per cent of cases did not evacuate because they did not expect the magnitude of storm. Conclusion: Warning messages delivered before and during emergencies should be conveyed in terms understood by the population at risk. We recommend that the results from this study be used to develop more effective messages to be used before future disasters

Rapid health assessments of evacuation centres in areas affected by Typhoon Haiyan

Introduction: Typhoon Haiyan caused thousands of deaths and catastrophic destruction, leaving many homeless in Region 8 of the Philippines. A team from the Philippine Field Epidemiology Training Program conducted a rapid health assessment survey of evacuation centres severely affected by Haiyan. Methods: A descriptive study was conducted whereby a convenience sample of evacuation centres were assessed on the number of toilets per evacuee, sanitation, drinking-water, food supply source and medical services. Results: Of the 20 evacuation centres assessed, none had a designated manager. Most were located in schools (70%) with the estimated number of evacuees ranging from 15 to 5000 per centre. Only four (20%) met the World Health Organization standard for number of toilets per evacuee; none of the large evacuation centres had even half the recommended number of toilets. All of the evacuation centres had available drinking-water. None of the evacuation centres had garbage collection, vector control activities or standby medical teams. Fourteen (70%) evacuation centres had onsite vaccination activities for measles, tetanus and polio virus. Many evacuation centres were overcrowded. Conclusion: Evacuation centres are needed in almost every disaster. They should be safely located and equipped with the required amenities. In disaster-prone areas such as the Philippines, schools and community centres should not be designated as evacuation centres unless they are equipped with adequate sanitation services

A community-based gastroenteritis outbreak after Typhoon Haiyan, Leyte, Philippines, 2013

Background: Three weeks after Typhoon Haiyan, an increasing number of acute gastroenteritis cases were reported in Kananga, Leyte, an area where evacuated residents had returned home two days after the disaster. An outbreak investigation was conducted to identify the source and risk factors associated with the increase of gastroenteritis. Methods: A case was defined as any person in Kananga who developed acute diarrhoea (≥ 3 times/24 hours) and any of the following symptoms: fever, nausea, vomiting or abdominal pain from 11 November 2013 to 10 December 2013. Active case finding was conducted by reviewing medical records, and a case-control study was conducted. Rectal swabs and water samples were tested for bacteriological examination. Results: One hundred and five cases were identified. Multivariate analysis revealed that consumption of untreated drinking-water was associated with illness (adjusted odds ratio: 18.2). Both rectal swabs and municipal water samples tested positive for Aeromonas hydrophila. On inspection of the municipal water system, breaks in the distribution pipes were found with some submerged in river water. Conclusion: This acute gastroenteritis outbreak was most likely caused by Aeromonas hydrophila and transmitted through a contaminated water source. This study highlights that areas less damaged by a disaster that do not require ongoing evacuation centres can still have acute gastroenteritis outbreaks. All affected areas should be monitored during a disaster response, not just those with evacuation centres. Boiling or chlorinating of water should also be recommended for all areas affected by disaster

Investigation of chikungunya fever outbreak in Laguna, Philippines, 2012

Background: In July 2012, the Philippines National Epidemiology Center received a report of a suspected chikungunya fever outbreak in San Pablo City, Laguna Province, the first chikungunya cases reported from the city since surveillance started in 2007. We conducted an outbreak investigation to identify risk factors associated with chikungunya. Methods: A case was defined as any resident of Concepcion Village in San Pablo City who had fever of at least two days duration and either joint pains or rash between 23 June and 6 August 2012. Cases were ascertained by conducting house-to-house canvassing and medical records review. An unmatched case-control study was conducted and analysed using a multivariate logistic regression. An environmental investigation was conducted by observing water and sanitation practices, and 100 households were surveyed to determine House and Breteau Indices. Human serum samples were collected for confirmation for chikungunya IgM through enzyme-linked immunosorbent assay. Results: There were 98 cases identified. Multivariate analysis revealed that having a chikungunya case in the household (adjusted odds ratio [aOR]: 6.2; 95% confidence interval [CI]: 3.0–12.9) and disposing of garbage haphazardly (aOR: 2.7; 95% CI: 1.4–5.4) were associated with illness. House and Breteau Indices were 27% and 28%, respectively. Fifty-eight of 84 (69%) serum samples were positive for chikungunya IgM. Conclusion: It was not surprising that having a chikungunya case in a household was associated with illness in this outbreak. However, haphazard garbage disposal is not an established risk factor for the disease, although this could be linked to increased breeding sites for mosquitoes

Chelonitoxism outbreak caused from consuming turtle, Eastern Samar, Philippines, August 2013

Background: On 21 August 2013, the Event-based Surveillance and Response system of the Department of Health, Philippines captured a foodborne illness event among residents of a coastal village in Eastern Samar, Philippines. The suspected cause was the consumption of a sea turtle found near the village. A team from the Department of Health was sent to conduct an outbreak investigation. Methods: A case was defined as any person in Arteche, Eastern Samar, who developed dry mouth and burning sensation in the throat from 15 August to 27 August, 2013. Severity of the disease was classified as mild, moderate or severe. We conducted records review, environmental investigation, interviews of key informants and a retrospective cohort study. Results: Sixty-eight cases were identified; four died (case fatality rate = 6%). All cases had a history of turtle meat consumption. Dose-dependent relationship was noted between amount of turtle meat consumed and the risk of illness. In the cohort study, consumption of turtle meat and turtle meat soup were associated with illness. Conclusion: This study identified turtle meat as the source of this foodborne outbreak and emphasized the dangers of consuming turtle meat. Other reported cases of turtle meat poisoning in the Philippines suggest that turtle consumption is an ongoing practice in the country. By publishing information about sea turtle poisoning outbreaks in the Philippines, we hope to raise awareness of the potential severe health effects from ingesting these endangered sea creatures

Lethal paralytic shellfish poisoning from consumption of green mussel broth, Western Samar, Philippines, August 2013

Background: In July 2013, the Philippines’ Event-Based Surveillance & Response Unit received a paralytic shellfish poisoning (PSP) report from Tarangnan, Western Samar. A team from the Department of Health conducted an outbreak investigation to identify the implicated source and risk factors in coastal villages known for green mussel production and exportation. Methods: A case was defined as a previously well individual from Tarangan, Western Samar who developed gastrointestinal symptoms and any motor and/or sensory symptoms after consumption of shellfish from 29 June to 4 July 2013 in the absence of any known cause. The team reviewed medical records, conducted active case finding and a case-control study. Relatives of cases who died were interviewed. Sera and urine specimens, green mussel and seawater samples were tested for saxitoxin levels using high performance liquid chromatography. Results: Thirty-one cases and two deaths were identified. Consumption of >1 cup of green mussel broth was associated with being a case. Seawater sample was positive for Pyrodinium bahamense var. compressum and green mussel samples were positive for saxitoxin. Inspection revealed villagers practice open defecation and improper garbage disposal. Conclusion: This PSP outbreak was caused by the consumption of the green mussel broth contaminated by saxitoxin. As a result of this outbreak, dinoflagellate and saxitoxin surveillance was established, and since the outbreak, there have been no harmful algal blooms event or PSP case reported since. A “Save Cambatutay Bay” movement, focusing on proper waste disposal practice and clean-up drives has been mobilized

Contact tracing the first Middle East respiratory syndrome case in the Philippines, February 2015

Background: Middle East respiratory syndrome (MERS) is an illness caused by a coronavirus in which infected persons develop severe acute respiratory illness. A person can be infected through close contacts. This is an outbreak investigation report of the first confirmed MERS case in the Philippines and the subsequent contact tracing activities. Methods: Review of patient records and interviews with health-care personnel were done. Patient and close contacts were tested for MERS-coronavirus (CoV) by real time-polymerase chain reaction. Close contacts were identified and categorized. All traced contacts were monitored daily for appearance of illness for 14 days starting from the date of last known exposure to the confirmed case. A standard log sheet was used for symptom monitoring. Results: The case was a 31-year-old female who was a health-care worker in Saudi Arabia. She had mild acute respiratory illness five days before travelling to the Philippines. On 1 February, she travelled with her husband to the Philippines while she had a fever. On 2 February, she attended a health facility in the Philippines. On 8 February, respiratory samples were tested for MERS-CoV and yielded positive results. A total of 449 close contacts were identified, and 297 (66%) were traced. Of those traced, 15 developed respiratory symptoms. All of them tested negative for MERS. Discussion: In this outbreak investigation, the participation of health-care personnel in conducting vigorous contact tracing may have reduced the risk of transmission. However, being overly cautious to include more contacts for the outbreak response should be further reconsidered

A retrospective cohort study on cassava food poisoning, Santa Cruz, Davao del Sur, Philippines, October 2015

Objective: On 2 October 2015, the Event-Based Surveillance and Response Unit of the Department of Health (DOH), Philippines received a report of foodborne illness cases in Santa Cruz, Davao del Sur. A team from DOH was sent to conduct an investigation to identify the implicated source and determine risk factors. Methods: A retrospective cohort study was done. A suspect case was defined as a previously well individual in Compound A, Santa Cruz who developed abdominal pain, headache, dizziness, diarrhoea or vomiting on either 1 or 2 October 2015. A confirmed case was a suspect case positive for cyanide in urine. Family members who prepared the food were interviewed. Urine specimens were collected to test for thiocyanate, and cassava tuber and soil samples were tested for cyanide and other chemicals. Result: Fourteen cases with two deaths were identified (case fatality ratio: 14%). All cases consumed cassava on 1 October 2015 except for one child who spat it out. Urine samples were all negative (36, 100%) for thiocyanate so there were no confirmed cases. The cassava sample had a cyanide level of 68.94 ug/g and was identified as bitter cassava, also known as a potentially dangerous kind. Insufficient food preparation was noted. In the retrospective cohort study, intake of cassava (RR = 208, 95% CI: 19.94–2169.32) was associated with the illness. Discussion: This study identified insufficiently processed cassava root crop as the source of the foodborne illness. The cassava consumed was the bitter variety that contains greater than 50 ug/g of hydrogen cyanide and requires thorough preparation before consumption. Community education was provided on identifying and preparing cassava appropriately