Staphylococcal poisoning during a village festival, Medina, Misamis Oriental, Philippines in 2014.

INTRODUCTION: On 18 August 2014, cases of food poisoning in San Vicente Village were reported to the Event-Based Surveillance & Response Unit of the Philippine Department of Health. An investigation was conducted to identify the implicated source, describe the outbreak and evaluate the risk factors. METHODS: A case-control study was conducted. A suspected case was a previously well individual of Medina who attended the village festival and developed abdominal pain and vomiting with or without nausea, diarrhoea and fever from 18 to 19 August. A confirmed case was a suspected case with a rectal swab positive for bacterial culture. Rectal swabs, water and food samples were sent to the national reference laboratories. Food source and consumption interviews and environmental inspections were conducted. RESULTS: Sixty-four cases and 123 unmatched controls were identified. The median incubation period was 1 hour 15 minutes. Five cases (8%) were positive for Staphylococcus aureus, one (2%) for Aeromonas hydrophilia and one (2%) for Shigella boydii. One (14%) water sample was positive for Aeromonas spp. Of the collected food samples, beef steak was positive for Staphylococcus aureus. Risk factors were consumption of Filipino-style beef stew (odds ratio [OR]: 6.62; 95% confidence interval [CI]: 2.90-15.12) and stir-fried noodles (OR: 3.15; 95% CI: 1.52-6.50). Prolonged serving time and improper food storage were noted. DISCUSSION: In this foodborne outbreak, Staphylococcus aureus was the likely causative agent. Meals were contaminated due to improper food handling practices. We recommend that a policy be created to mandate that village-appointed food handlers undergo food safety training.

Epidemic hysteria following the National School Deworming Day, Zamboanga Peninsula, Philippines, 2015.

INTRODUCTION: In July 2015, the Philippines conducted a school-based mass drug administration using albendazole for soil-transmitted helminths infection. Reports of adverse events were subsequently made through the event-based surveillance system, mostly from the Zamboanga Peninsula on the island of Mindanao. A team from the Epidemiology Bureau investigated the reports of adverse events following mass drug administration (AEFMDA). METHODS: Five schools were identified for the investigation which comprised an unmatched case-control study, key informant interviews and laboratory examinations. AEFMDA cases were students who had sudden onset of abdominal pain, vomiting, diarrhoea, loss of consciousness, headache or dizziness within 24 hours after intake of deworming tablet; controls were healthy students who did not develop signs and symptoms after deworming. RESULTS: Most (85%) of the 7313 AEFMDA cases reported nationwide were from Zamboanga Peninsula. Most reports were made after rumours of deaths following deworming and of the use of expired drug were spread through the region. Many parents sent their children to hospital, even if asymptomatic. The case-control study found that being an AEFMDA case was associated with no history of previous deworming (odds ratio = 4.08, 95% confidence interval: 1.77-9.42). DISCUSSION: The investigation concluded that epidemic hysteria was the cause of the increased number of AEFMDA cases in the Zamboanga Peninsula. The false information, aggravated by social media, caused panic and an increase in reporting. Some cases had no history of deworming, and they may not have been aware that albendazole is safe and that side-effects are expected. Risk communication before, during and after future national deworming programmes are recommended to prevent unnecessary reporting of AEFMDA.

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.