Outbreak Investigation report: Multistate Hepatitis A outbreak amongst European travelers coming from Egypt

Introduction

The sudden occurrence of any outbreak disease makes it a critical concern to any public health sector in any nation. The possibility of the disease spreading to different parts of the nation and affecting a larger number of individuals further justifies its deadly nature. It is vital that proper investigations of the outbreak be carried out to identify its possible causes and to device suitable strategies to prevent the reoccurrence of that disease. This report presents an analysis of the Hepatitis A outbreak that was reported by European Union countries. The report presents a discussion on how the investigation process was conducted and also on the possible sources of the outbreak that were identified. Ana analysis of the approaches that can be adopted to prevent the reoccurrence of the outbreak is also reported.

Background Information

The Hepatitis A virus outbreak in the European nations was reported between November 2010 and April 2013. On 15th of April 2013, the Norwegian Institute of public health reported through the Epidemic intelligence information systems for food and waterborne diseases and Zoonoses platform, an increase in the rate of hepatitis A infection in European travelers coming from Egypt (Sane, MacDonald, Vold, Gossner & Severi, 2013). The rates were higher than the normal annual rate ever reported in the region; as such Norway notified other European countries to find whether they had similar cases. A total of 14 European nations reported 107 cases of Hepatitis A infection from the European travelers coming from Egypt.

It is reported that the incidence of Hepatitis infection has significantly declined in most countries of the European Union. This is due to the improved hygiene levels in the region as well as enhanced living conditions for most of the citizens (Lenzer, 2015). Hepatitis A infection has however remained common amongst the European travelers. In this case, the infection was mostly experienced amongst the travelers coming from Egypt as such; Egypt was indicated as the major source of the infection (Sane, MacDonald, Vold, Gossner & Severi, 2013). The fact that Hepatitis virus infection has remained highly endemic in Egypt further suggested the region as the potential source of the infection (Arias, 2010). It was also observed that 21 cases out of those investigated were affected by a strain having an identical RNA sequence further indicating a common source outbreak.

An investigation team under the coordination of the ECDC and involving the world health organization, public health institute in the European Union nations as well as the Egyptian public health authority was conducted to determine the common exposures among the cases identified. The investigation was also conducted to determine whether vaccination on travelers should be enhanced. The investigation findings indicated that orange juice, raw vegetables, fresh fruits, berries and different salads were the major sources of food consumed by the cases that stayed in the same hotel. However, exposure to orange juice, mango and fresh strawberries were common amongst the cases that were included in the study. Thus mango, orange juice and strawberries were the sources of food implicated in the outbreak.

Investigation of the Outbreak

Confirm that this was a real outbreak

According to Chandriani et al., (2013) a disease outbreak is sudden occurrence of several cases of the disease. These disease cases are normally in excess of what is expected by the public health authorities. Klevens, Liu, Roberts, Jiles & Holmberg (2014) has also pointed out that the disease is considered an outbreak when the disease cases that exceed the normal levels can be traced to have been within a common or confined geographical region. To determine that the disease cases are in case, the public health officer of the region needs to consider the annual rates of the disease reported and compare with the new rates to ascertain whether there is a significant difference (Praveen et al., 2013). In the event that the number of cases are very high than the expected annual rates then the disease is considered an outbreak.

Focusing on the above definitions, the Hepatitis A infection reported amongst the travelers is a real outbreak. It is reported that the number of the European travelers infected with the Hepatitis A virus were higher than the normal levels reported. In addition, the disease occurred suddenly and had effects in a larger number of individuals within the short period of time. It is also reported that the higher number of those infected had travelled to Egypt and occupied the same hotels suggesting a common source of the outbreak. The fact that the disease had a common source, occurred suddenly and affected a higher number of individuals more than the normal rates expected justifies it as a real outbreak disease.

Case Definition

According to Klevens, Liu, Roberts, Jiles & Holmberg (2014) a case definition is a criteria adopted to determine whether an individuals should be included as a case or not. The time and place of illness and clinical features of an individual are used in the classification of cases in epidemiology research. Harries et al., (2014) has indicated that a case can either be a confirmed case where the clinical symptoms of the disease has been confirmed in the laboratory to be caused by an identified organism, a probable case where an individual has clinical symptoms that are yet to be confirmed on the disease causing the system, and possible where an individual has few clinical symptoms.

In the Hepatitis A disease outbreak, a probable case was defined as an individual with Hepatitis A symptoms and with a laboratory confirmed Hepatitis A infection (Sane, MacDonald, Vold, Gossner & Severi, 2013). The individual must have reported the symptoms after 1st of November 2012 and had travelled to Egypt 2-6 weeks prior to the onset of the symptoms. The individual was also required to have reported no other known exposure to Hepatitis A disease. A confirmed case was defined as a probable case infected with Hepatitis Virus containing the RNA sequence that matches the outbreak sequence that was initially isolated from the Norwegian first case. According to Hughes, Naik, Sengupta & Saxena (2014) case definition process is vital to identify the individuals to include or exclude from the epidemiology investigations. This process was therefore important in the selection process to identify the persons to exclude or include in the investigation process that sought to determine the major cause of the disease as well as the measures that needs to be put in place to prevent the reoccurrence of the outbreak (Waldram et al., 2015).

Case Finding

In the process that the outbreak is reported in different region, there is need to have a centralized platform where all the cases observed are reported. These cases needs to be reported as either confirmed or probable cases for the investigation process to be carried out properly (Dhankhar et al., 2015). This is necessary in ensuring that all the confirmed cases are included in the investigation process for accurate findings to be obtained (Ly et al., 2012).  Initially, only the confirmed cases were included in the epidemiology investigations touching on any health issues, however, recent developments have seen most investigators include even the probable cases that had come in contact with the confirmed cases with the reasoning that they are likely to contact the disease. As Donnan, et al (2012) indicates, excluding the probable case may not also be wise since having the symptoms is a sure way of indicating their high possibility of contacting the disease.

In the Hepatitis outbreak that was reported in the European nations, the cases were obtained from the ECDC. The countries were required to report to report the cases meeting the confirmed and probable case definition to the ECDC through the EPIS-FWD platforms. These nations were expected to report the number of cases meeting the confirmed case definition as well as the number of cases meeting the probable case definition. They were also required to provide demographic characteristics, travel details and clinical features of the included cases.

Case description and the nature of the outbreak

The cases and the controls that were included in the investigation carried out were described in terms of country of origin, sex and age. This approach was effective in availing information on the age groups that are mostly affected by the Hepatitis infection. Moreover, classifying the cases in form of their countries of origin is also important in ascertaining the extent of the outbreak and its intensity in different nations.

Foods that were served in the hotels were indicated as exposure. This was to identify the source to implicate as the source of the Hepatitis A infection. The confirmed and probable cases were asked to indicate the nature of the food that they had consumed while in the hotel. The associations between the exposures identified and the outcome reported by the cases were then determined to identify the possible foods that can be implicated to the infection.

From the investigation report, the first observation on the increase in the cases of Hepatitis Infection was reported on 15th of April 2014. At this time, most of the cases had symptoms of the infection. The case definition has only included travelers who reported symptoms from 1st November to ensure that only those who were infected during that period are included in the investigation. According to Von et al., (2014) the incubation period for Hepatitis A virus varies from 15-50 days, and in certain cases might even be higher than 50 days. In order to include all confirmed and probable cases in the investigations, it is vital to look at the incubation period of the virus when deciding on the time of disease occurrence (La Rosa, et al., 2014). In this case, the disease outbreak was first reported in April, as such, the cases must consider those who reported the symptoms from as early as November as well as those who reported the symptoms as late as April since the incubation period of the virus varies and can be expressed at different times on different people.

Development of the hypothesis

From the investigation conducted, majority of the European travelers who has the symptoms had been staying in the all-inclusive hotel located along the Red Sea. All the confirmed and the probable cases had been staying in this hotel. These travelers were exposed to foods such as orange juice, strawberries and mangoes. It can be hypothesized that the consumption of mangoes or strawberries at the all-inclusive hotel located along the Red Sea caused the Hepatitis A infection that was reported amongst the European travelers coming from Egypt.

From the earlier laboratory tests conducted, it was discovered that 21 cases out of the 107 reported cases, had Hepatitis virus of the same RNA sequence, this indicated that the cases contacted the virus from a common source. Further analysis conducted using the questionnaires indicated that 35 out of 43 cases interviewed had been staying in the all-inclusive hotel positing it as the major source of the infection. These cases also indicated that they had either consumed mangoes and/or strawberries while staying in the hotel. Hepatitis A is transmitted through the consumption of contaminated foods and drinks. In addition, the transmission can be observed via feacal/oral route when one gets in close contact with an infected person (Dimitrova et al., 2014). The fact that these travelers had consumed a common food and were in close contact during their stay in the hotel justifies the food and the region as the potential source of the infection. The above information provided insights and better understanding on the hypothesis that the European travelers contacting the Hepatitis infection through the consumption of contaminated mangoes and/or strawberries while staying in the all-inclusive hotel along the Red Sea.

Hypothesis Testing

In a case control study, hypothesis testing is conducted by carrying out a comparison between the confirmed cases and the control. In this study, the control included the individuals who has been staying in the all-inclusive hotel at the same time as the confirmed and probable cases but did not report any symptoms of Hepatitis infection. Control cases were however excluded if they had a history of Hepatitis A infection of had knowingly been infected with Hepatitis A.

The case-control study focused on determining the association between the disease outcome and exposure. According to Ibrahim (2014) a case-control study was more appropriate in this scenario since the disease had already progressed and the work of the investigator was to determine the exposures. In this case, the most appropriate method is to include the cases (individuals who had reported the disease symptoms) and control (individuals who were at the same risk of contracting the disease but did not) in the investigations to determine their exposures and link it as the source of the disease. This is contrary to the cohort studies where the investigator has already identified the exposure and seeks to establish the association between the exposure and the disease outcome (Waldram et al., 2015). Cohort studies are mainly applicable where a disease has not progressed and an investigator uses two different groups of individuals to evaluate the possible effects that exposing them to certain environments might have on them (Ibrahim, 2014). This explains why a case-control study as opposed to a cohort study was adopted in this investigation.

From the case-control study conducted, it was obtained that most of the cases had consumed mangoes and/or strawberries at the hotels. Thus, the consumption of the mangoes and/or strawberries caused the Hepatitis A infection amongst the travelers.

Discussion and conclusion

Hepatitis A infection can cause severe illness to an individual, mostly the older individuals. The direct and indirect causes that are associated with Hepatitis A infection can also not be underestimated (Montaño-Remacha et al., 2014; Hughes, et al., 2014). It is observed that majority of the infection cases of Hepatitis A under u in hospitalization of the infected persons further indicating the severity nature of the disease. According to Mihigo et al., (2013) this disease is mainly transmitted through the consumption of contaminated foods or water or through the feacal/oral routes by being in contact with an individual who has the infection. Proper hygiene is therefore needed to control the spread of the disease.

In the investigation presented above, the European travelers mainly contacted the infection through the consumption of the contaminated mangoes and/or strawberries. From the case-control study conducted, these fruits had the highest level of association with the disease outcome, however, other fruits such as orange juice and raspberries can also not be ruled out since some of the cases reported that they had consumed them. More controls would have been needed to know whether they were real exposures of not (Melhem, Talhouk, Rachidi & Ramia, 2014). Nevertheless, it was observed that the poor hygienic conditions within the hotels, led to the contamination of the fruits that thus caused the infection. According to Dimitrova et al (2014) strawberries are highly plausible due to their small nature hence difficult to wash, as such can the contamination of the fruit could have occurred during irrigation or washing of the fruit by the hotel personnel. The failure by the European traveler to get vaccinated for the virus as well as their assumption that the operations in an all-inclusive hotel are highly hygienic contributed to them contacting the infection. It is therefore important to get vaccinated as well as ensure any fruits or food generally is properly handled prior to consumption.

Lessons learnt and recommendations

  • This investigation has highlighted a higher risk of contacting the infection amongst non-immune European travelers. It is recommended that any individual travelling to high endemic regions such as Egypt get vaccinated to prevent the Hepatitis A infection.
  • It is observed that some of the travelers were not aware of the importance of the vaccination; as such awareness on the significance of the vaccination especially to travelers should be improved in all the public health institutions in the European nations.
  • Hepatitis A is highly endemic in Egypt; the Egyptian Public Health Authority should ensure that all hotels and other facilities offering foods to local as well as tourists practice the highest level of hygiene to prevent transmission of the diseases. This can be done by enforcing hygienic standards of operations that must be adopted by every hotel operator.

Leave a Reply