Investigating Association between Chinese Frozen Berries and HAV Infection in Australia - Research Paper Example

Case-control Research Proposal: Investigating Association between Chinese Frozen Berries and HAV Infection in Australia Course Date Abstract As of 2005, it was estimated that on any given day, an estimated 11,500 Australians suffer food poisoning. Combined, food poisoning cost the country approximately AU$ 2.6 billion; this figure must be higher today. Earlier in 2015, the Australian Department of Health reported that of the 65 cases of HAV infection that had been reported by then, 27 were associated with imported Chinese frozen berries. However, there has been a documented scientific study to verify or refute the alleged association. Consequently, the researcher proposes a case-control study to investigate the allegation. A review of the literature reveals that the HAV is capable of surviving in and being transmitted through frozen foods. By design, the proposed study is a case-control study. The 27 people alleged to have contracted the virus after eating the said berries will serve as the cases while the remaining 38 will constitute the controls. The particulars of the participants will be obtained from the Department of Health. The results will be analyzed using SPSS. Data analysis will be followed by a discussion of the same and relevant recommendations made. Case-control Research Proposal: Investigating Association between Chinese Frozen Berries and HAV Infection in Australia Introduction In Australia, it is estimated that on any given day, there are 11,500 cases of food poisoning. In a year, food poisoning costs the country AU $2.6 billion (Center for Science in the Public Interest, 2005). As of March 17, 2015, 65 cases of Hepatitis A had been reported in Australia compared to 81 cases same time last year(Australina Government, 2015). Of the 65 cases, 27 were linked to Chinese frozen berries manufactured by Nanna. In all the 27 cases, the victims reported having eaten Nanna’s frozen berries within fifteen to fifty days of the onset of the symptoms. The strong epidemiological association is has been strengthened by genotyping. Following the incident, four products including the 1kg pack of Nanna’s Mixed Berries, were recalled from the Chinese market. Only Nanna’s Mixed Berries had been linked with the outbreak; the other three products were recalled as a precaution. During its media update on the outbreak in March, the Department of Health advised anyone who had eaten the recalled frozen berries and felt unwell to see their GP soonest possible. China is the world’s largest agricultural economy and one the leading agricultural exporters (Food and Water Watch, 2011). However, since the 1990s, Chinese food standards have fallen below international standards, raising serious concerns over consumer safety (Ortega, Wang, Wu, Olynk, & Bai, 2012). The main factor that comprises Chinese food security is the difficulty encountered in monitoring food production standards throughout the country. The situation arises because of the vast number of smallholder farmers spread across the country. Most of these farmers rely on agrochemicals to sustain high yields, leading to high chemical content in Chinese foods(Hsietang, et al., 2012). Thus, animal products suchas poultry exhibit high antibiotic residues whereas plant products such as cabbage and tea contain high contents of pesticides(Wang, Mao, & Gale, 2008). Research Purpose While there were reports by the Australian Department of Health that 27 of the 65 reported cases of Hepatitis A Virus (HAV) as of March 17 this year were linked to Chinese frozen berries manufactured by Nanna, there is no documented scientific study to back the claim. The purpose of this research is to verify the allegation using a case-control study. A case-control study helps determine if an exposure leads to an outcome(Courtright & Lewallen, 1998). By exposure is meant an environmental, behavioral or clinical factor that could influence the occurrence of a disease or death(Courtright & Lewallen, 1998). Smoking, low birth weight, living in a heavily polluted industrial area and the use of antidepressant are all examples of exposures. For this study, the eating of Nanna’s frozen berries is the exposure. An outcome is either a disease or death(Courtright & Lewallen, 1998); for this study, HAV is the outcome. Literature review HAV infects the liver with a disease that is characterized by the inflammation of the liver and the development of jaundice. HAV infection can be asymptomatic with no clinical symptoms in mild cases, or it can lead to severe damage of the liver in critical cases. In most developing countries, HAV is endemic, but sporadic in developed countries. Description of the organism HAV belongs the Picornaviridae family of viruses and the Hepatovirus genus(Normann, et al., 2008). The Picornaviridae family comprises small, non-enveloped viruses that measure 25-28 nm. The viruses are stronger and survive better in the environment than enveloped viruses such as the herpes simplex virus. HAV particles comprise one strand of RNA confined within an icosahedral-shaped protein shell (Rozenberg, Deback, & Agut, 2011). HAV has six genotypes (I-VI) and one known serotype. Genotypes I-III are associated with human disease, whereas genotypes IV-VI are found in Old World monkeys. Each of genotypes I-III is further divided into types A and B. Most human strains of HAV belong to genotypes I and III (US Food and Drug Adminisatraion, 2012). Usually, the isolates from a given HAV outbreak belong to the same genotype (Normann, et al., 2008). Growth and survival characteristics HAV needs specific living host cells to multiply. The implication is that that quantity of HAV in contaminated food cannot grow during processing, transportation or storage(Koopmans & Duizer, 2004). However, they can still survive outside the host for extended periods. Its survival is influenced by environmental factors such as food composition, chemicals, pH and temperature. Under conditions that simulate typical environmental exposure, HAV continues to be infectious even after being dried and stored for up to thirty days. HAV has also been demonstrated to survive for up to sixty days on non-porous material such as china, latex and aluminum, though it does not survive as well on these materials(Koopmans & Duizer, 2004). HAV survives on human hands for up to four hours, during which it remains infectious and can be transferred between hands and non-living surfaces. HAV survives in seawater, fresh river water, groundwater and untreated tap water. However, there has been no standard protocol by which to estimate the average survival of HAV in water. HAV can survive on fresh produce stored at 40C for up to nine days. HAV has been found to resist temperatures 600C. At 610C, however, HAV particles disintegrate releasing their viral RNA. A 2008 study showed that when stored under frozen conditions, HAV contaminated berries can support the survival of the virus for up sixty days(Butot, Putallaz, & Sanchez, 2008). HAV highly resists solvents and acidic conditions. Mode of transmission HAV is transmitted through the faecal-oral route either by person-person contact or the intake of contaminated food or water (Guillois-Becel, et al., 2009). Person-to-person transmission is likely to involve young children with asymptomatic infection. However, most HAV outbreaks result from the faecal contamination of one source of food or water(Guillois-Becel, et al., 2009). Foods such as shellfish may become contaminated in their growing areas while crops may become contaminated through irrigation or when they come into contact with sewage water. Infected food handlers may also contaminate food. Foods that are eaten raw or only slightly cooked are most often implicated in HAV outbreaks. Also implicated are foods that are extensively handled prior to consumption such as salads and sandwiches. Travel to areas with HAV outbreak is known to be a risk factor. The transmission of HAV via blood and blood products is rare. Methodology Research Design By design, the proposed research is a case-control study. As already pointed out, the essence of this type of study is to help in determining if an exposure leads to an outcome(Courtright & Lewallen, 1998). In the case of this study, the purpose is to ascertain whether the 27 cases of HAV linked to Chinese frozen berries by the Australian Department of Health earlier this year were indeed associated with the consumption of the alleged berries. In order to carry out the study, the researcher will first identify the cases that is, the 27 HAV cases linked to Chinese berries and the controls, that is, a group known to be free of the Chinese-berries associated HAV. Then, the research will look back in time to find which subjects in each group were exposed to the alleged risk, that is, Nanna’s frozen berries, comparing the frequency of exposure of both groups(Langholz & Richardson, 2009). A case-control study is always retrospective in the sense that it starts with an outcome and traces back to interrogate exposures. It is this tracing back to discover exposure that makes the study retrospective, not the fact that the researcher uses previously collected data. As the research involves human beings, the researcher will seek the approval of the local Human Research Ethics Committee (HREC). HRECs are established by organizations and registered with the National Health and Medical Research Council (NHMRC). HRECs review research proposals that involve human beings to safeguard the safety of subjects and uphold ethical research practices. Besides the research proposal itself, the researchers student identification card and research letter from the Department will be useful in obtaining HREC approval. Ethical considerations Respect for people: Respect for people and their rights requires that the researcher observes at least to principles. The first principle is autonomy and requires, for the purpose of this research, that subjects participate in the investigation out of their free will, without coercion(National Ethics Advisory Committee (NEAC), 2012). Thus, even as the researcher seeks the participation of all the 65 people reported to have been infected by HAV, such total participation is subject to their consent. The second principle requires that people whose autonomy is diminished or impaired be protected. For the investigation, such people may include minors whom the researcher will access with the permission of their parents or guardians. Justice: Justice requires that a case-control study be designed such that the benefits and burdens of the study are fairly distributed among participants and that for any participant, there is a balance between burdens and benefits. In this regard, the proposed study is fair at it gives each of the 65 potential candidates a chance to participate, subject to their consent. Unfortunately, as far as locating the participants is concerned, the Department of Health will bear the bulk of the burden. Beneficence and non-maleficence: This principle requires that the risks associated with the study be reasonable relative to the expected benefits. As the proposed research is observational, there will be minimal risk involved. Integrity: The researcher undertakes to advance knowledge by undertaking an honest, thoughtful and rigorous inquiry and analysis and being accountable for their activities. Diversity: Whereas the researcher has no details yet of the 65 potential participants, it is believed that they will present a diverse group. Conflict of interest: The researcher does not envision any conflict of interest in the study. However, should it emerge in the course of the study, the researcher will communicate the same to sponsors, participants and, if necessary, to the HREC. Cases The 27 people reported to have contracted HAV as a result of eating Nanna’s frozen berries will constitute the cases for this study. Their particulars will be obtained from the Department of Health. Again, the researcher’s student identification documents – their student identification card and letter of introduction issued by their Department – will be useful in accessing this information. Controls The controls chosen for a case-control study should be similar to the cases in as many ways as possible(Courtright & Lewallen, 1998). The set of factors chosen to define the similarity of cases and controls are known as the “matching criteria”. For instance, it would be inappropriate to compare a group of controls who underwent plastic surgery with a group of cases with traumatic corneal lacerations. Consequently, the controls will be drawn from the remaining 38 people whose HAV infection was not associated with Nanna’s frozen berries. The rationale for taking all of the remaining 38 people instead of 27 to match the cases is that enrolling more than one control for every case enriches the findings of a case-control study(Courtright & Lewallen , 1998). However, beyond two controls for every case, there are no statistical gains (Courtright & Lewallen, 1998). Again, the particulars of the 38 will be obtained from the Department of Health. Data Collection For all the subjects in both groups, the researcher will seek to find out if they had eaten Nanna’s frozen berries (this is the risk factor) within fifteen to fifty days of being diagnosed with HAV. This is the estimated period it takes the HAV symptoms to manifest (Normann, et al., 2008). The researcher will obtain the clinical records of all the 65 diagnoses from the Department of Health. To find out subject exposure to risk, the researcher will interview all the 65 subjects. Therein are some inherent limitations. First, subjects may have difficulty recalling all the details with accuracy. This may especially be the case for the control group; as for the cases, they are more likely to scrutinize the past and recall the details of negative exposures. The other limitation is that the researcher may have no way of verifying subject accounts. Analysis In the analysis stage, for each, the researcher will calculate the frequency of exposure to Nanna’s frozen berries. For each group, the researcher will obtain the odds ratio which will be a measure of the strength of the association between Nanna’s berries and the incidence of HAV(Clarke , et al., 2011). The odds ratio will be arrived at by taking the number of subjects who will have reported eating Nanna’s berries and dividing that number by the total number of subjects in the group. The researcher will also calculate the confidence interval for each odds ratio using SPSS. A confidence interval that includes 1.0 would imply that the association between the exposure and the risk is the result of chance alone and has, therefore, no statistical significance(Langholz & Richardson, 2009). Also, an odds ratio without a confidence interval will not be very meaningful. Results Whereas a case-control study may reveal an association between an exposure and an outcome, it does not reveal causation(Hardell, Carlberg, & Mild, 2011). In terms of the proposed investigation, the researcher may not conclude that Nanna’s frozen berries were responsible for 27 of the 65 HAV infection cases reported in Australia earlier this year. The inability of the case-control study is one of its major limitations. Another limitation of the research design is that it cannot provide any information on the prevalence or incidence of a disease as no measurements are made on the sample and generalized to the population. The limitations notwithstanding, a well-designed case-control study can provide valuable information. Sometimes, it is the only ethical way of investigating an association. Discussion, Conclusions & Recommendations In this section, the researcher will undertake a discussion the findings of the study and their implications. In discussing the findings, the researcher will point out the limitations of the study. Already, some have been pointed out in this proposal and include the fact that, as far as the intake of Nanna’s frozen berries, the researcher will rely solely on the oral accounts of the participants and will have no means of verifying them. The limitation of this method of collecting data is that the participants may not recall past details accurately(Hardell, Carlberg, & Mild, 2011). Another limitation of the research is that, at best, it will establish the association between the consumption of the frozen berries of the said manufacturer and HAV infection; it will not be able to ascertain that the intake of the berries caused 27 of the 65 cases of HAV infection(Butot, Putallaz, & Sanchez, 2008). The researcher will also make inferences from the findings such as the possibility of the frozen berries have been contaminated at the point of consumption as opposed to the points of production, transportation and storage. Depending on the outcome of the study, the researcher will make a number of recommendations. In the event that an association is linked between Nannas frozen berries and HAV infections the researcher will recommend medical and policy measures in addition to the withdrawal of Nanna’s products from the Australian market, a measure that has already been taken. Some of the recommended medical measures would include further research to monitor the long-term effects of food-induced HAV infection in the subjects(Butot, Putallaz, & Sanchez, 2008). Policy recommendations would include a raft of measures to enhanced frozen food safety in the country. References Australina Government. (2015). Hepatitis A linked to Frozen Berries. Canberra: Australian Government. Butot, S., Putallaz, T., & Sanchez, G. (2008). Effects of sanitation, freezing and frozen storage on enteric viruses in berries and herbs. International Journal of Food Microbiology, 126.1-2 30-35. Center for Science in the Public Interest. (2005). Local and Global: Food Safety around the World. Washington, DC: Center for Science in the Public Interest. Clarke, G., Carl, A., Petterson, F., Cardon, L., Morris, A., & Zondervan, K. (2011). Basic statistical analysis in genetic case-control studies. National Protocol, 6.2121-133. Courtright, P., & Lewallen, S. (1998). Epidemiology in Practice: Case-Control Studies. Community Eye Health Journal, 11.2857-8. Food and Water Watch. (2011). A Decade of Dangerous Food Imports from China. Wahington, DC: Food and Water Watch. Guillois-Becel, Y., Coutrier, E., le Saux , J., Roque-Afonso, A., le Guyader, S., le Goas, A., . . . Vaillant, V. (2009). An oyster-associated hepatitis A outbreak in France in 2007. Eurosurveillance, 14(10)19144. Hardell, L., Carlberg, M., & Mild, K. (2011). Pooled analysis of case-control studies on malignant brain tumors and the use of mobile and cordless phones including living and deceased subjects. International Journal of Oncology, 381465-1474. Hsietang, H., Huang, H., Ling, M., Chen, Y., Huang, L., Wu, C., & Chiang, C. (2012). Total dietary Studies and Food Safety Assessment in Taiwan-Food Preservatives as an Illustration. Journal of Food and Drug Analysis, 20.14744-763. Koopmans, M., & Duizer, E. (2004). Foodborne viruses: An emerging problem. International Journal of Food Microbiology, 9023-41. Langholz, B., & Richardson, D. (2009). Are nested case-control studies biased? Epidemiology, 20.3321-329. National Ethics Advisory Committee (NEAC). (2012). Ethical Guidelines for Observational Studies: Observational research, audits and related activities (Revised ed.). Wellington: National Ethics Advisory Committee (NEAC). 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