Systematic Review: Gastroenteritis Outbreaks & Climate Change Impact

This systematic literature review investigates the evidence linking gastroenteritis outbreaks to climate change and weather patterns. It uses databases like CINAHL, COCHRANE, PubMed, and MEDLINE to analyze articles published between 2004 and 2018, focusing on the impact of weather variability and extreme events like El Nino and La Nina on the spread of viral gastroenteritis. The review highlights the global prevalence of gastroenteritis, its causes (including norovirus, rotavirus, E. coli, Campylobacter, and Salmonella), and the role of climate change in altering the distribution and transmission of pathogens. It emphasizes the interplay between human activities, climate change, and the incidence of infectious diseases, addressing the importance of public health measures to mitigate the impact of climate change on gastroenteritis outbreaks.

Running head: WHAT EVIDENCE ARE THEE THAT GASTROENTIRITIS OUTBREAK IS
ASSOCIATED WITH CLIMATE CHANGE/ WEATHER PATTERNS
WHAT EVIDENCES ARE THERE THAT GASTROENTERITIS OUTBREAK IS
ASSOCIATED WITH CLIMATE CHANGE/ WEATHER PATTERNS
Systematic Review Literature
Student Name: MAKINDE OLUWAMAYOWA
Public Health Practice (7707 MED)
Course Supervisor: Dr. Megan Young

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WHAT ARE THE EVIDENCES THAT GASTROENTERITIS OUTBREAK ARE
ASSOCIATED WITH CLIMATE CHANGE/WEATHER PATTERN
Abstract
The systematic review literature has been focused on obtaining evidence to whether
Gastroenteritis outbreaks are associated with weather patterns/climate change. The objective of
this research is to establish the association between climate change and its effect on
gastroenteritis by reviewing the current literature available and finding evidence from them. The
methodology used for this project in systemic literature review using the databases such as
CINAHL, COCHRANE, PubMed and MEDLINE using the keywords Gastroenteritis and
Climate Change, weather changes. The studies chosen for the project are published from January
2004 to December 2018. On the basis of relevance to the research question the articles were
reviewed and duplicates and unrelated articles were omitted from the project. The research
project objective was to find the evidence to impact of weather variability on the incidence of
gastroenteritis. What will be the effect of Extreme weather events such as Quasi-Biennial
Oscillation, El Nino, La Nina, and local level meteorological changes such as droughts, floods on
the spread of viral gastroenteritis.

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WHAT ARE THE EVIDENCES THAT GASTROENTERITIS OUTBREAK ARE
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Table of Contents
Abstract............................................................................................................................................1
Background......................................................................................................................................3
Prevalence of gastroenteritis........................................................................................................3
Causes of climate change.............................................................................................................4
Relation between climate change and gastroenteritis..................................................................5
Relation in between climate change and distribution of pathogens............................................6
Rationale..........................................................................................................................................8
Aim..................................................................................................................................................8
Objectives........................................................................................................................................8
Methods...........................................................................................................................................9
The required resources.....................................................................................................................9
Results..............................................................................................................................................9
Discussion........................................................................................................................................9
Research significance....................................................................................................................15
Conclusion.....................................................................................................................................16
References......................................................................................................................................17

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WHAT ARE THE EVIDENCES THAT GASTROENTERITIS OUTBREAK ARE
ASSOCIATED WITH CLIMATE CHANGE/WEATHER PATTERN

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WHAT ARE THE EVIDENCES THAT GASTROENTERITIS OUTBREAK ARE
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Background
The infectious gastroenteritis is one of the present health issues worldwide and the
primary symptom of this disease, diarrhoea lead to the death of almost 3 million people and
cause diseases to almost 1 million people throughout the world. In the different industrialised
countries the death rates are very high in comparison to the birth rates mainly because of the
occurrences of intestinal problems. Recently due to changes in the global climate, scientists have
become very interested in doing researches on the relation between the changes in the climate
and different climatic factors and the occurrence of the gastrointestinal problems. It has been
found that the gastrointestinal diseases are very much related with the changes in the sudden
climatic conditions and weather patterns. Gastroenteritis is the inflammation of the stomach and
the large and small intestines which means gastroenteritis means the inflammation of the whole
gastrointestinal tract (Cronk, Slaymaker & Bartram, 2015). It also known as infectious diarrhea
and usually called Stomach Flu, but it has no relation to Influenza. Diarrhea, abdominal pain,
lack of energy, fever, and vomiting are the main symptoms associated with gastroenteritis.
(Cronk, Slaymaker & Bartram, 2015). The occurrence of gastroenteritis due to the changes in
the weather patterns can be decreased if the human activities against the environment decreases.
Prevalence of gastroenteritis
Infectious gastroenteritis is a common illness in developed and developing as well as
underdeveloped countries. In United States, gastroenteritis is responsible for 3.7 million hospital
visits and 135,000 to 220,000 paediatric visits, and gastroenteritis also contributes to the deaths
of 150 to 300 children of below 5 years within a few period of time (Singh, A., Fleurat, M.,

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Kwon, K. T., & Whiteman, P., 2010). In Australia gastroenteritis infection is prevalent and
affects an estimated 17 million people per annum (Harley et al.,2011).
The main causes of gastroenteritis are the infections cause by some viruses and bacteria
and rather than by the infection caused by the parasitic infections. The main viruses which cause
this disease are Novovirus and Rotavirus (Helms, A Richard, 2006). Among the bacteria the
main causative agents are Escherichia coli, Campylobacter and Salmonella are the primary
causes of gastroenteritis (Webber, Roger., 2009). Alone in the United States it is estimated that
one million Campylobacter gastroenteritis cases were recorded every year (Scallan et al.,2011).
Salmonella is also one of the leading cause of acute gastroenteritis throughout the world. In the
United States, salmonellosis is responsible for 1.4 million cases of gastroenteritis including
15,000 hospitalizations and 400 deaths each year. (Callaway et al., 2008).
Causes of climate change
Climate change or Weather Change is the long-term shifts in climate patterns. Due to
increase in population, human activities against the nature and for the natural products are
increasing. Increasing human population is consuming the natural products in such a way that it
is leading to the changes in the climate. The massive rate of deforestation is increasing the
atmospheric temperature of the Earth and thus climate change is occurring ultimately. Due to the
changes in the climate humans and animals are suffering a lot as the changes in climate is
affecting the health conditions of animals. The death rate has increased much more than it was
few years before. Variations in the climatic conditions play a major part in deciding the
behaviour patterns and activities of human beings and other organisms (Viboud et al., 2004) and
hence climate change patterns may influence patterns of disease transmission (Kuhn et al., 2005).

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It can be understood from the figure that the changes in the climate and the occurrence of
the infectious diseases are very much interrelated. In one side it can be seen that that the changes
in human activities impact the climate negatively as the increase in human population increases
the demands of the people. To meet the increasing demand of the people, deforestation are done
and people are contaminating the rivers and using water from rivers. This automatically changes
the climate (McIver et al., 2016) Lack of trees will lead to increase in the temperature of the
Earth, scanty rainfall and many other things. Due to this increased temperature, pathogens which
require higher temperature to grow will start growing and will infect humans. People will suffer
from disease and also the disease will spread from one person to another Sometimes even, the
organisms get adapted to the normal temperature also. Some bacteria get involved the food items
and also get mixed with underground water and cause gastroenteritis (Maal-Bared et al., 2012).
Supporting this theory is the seasonality of infection with pathogens such as rotavirus,
salmonella and campylobacter. Rotavirus has a peak rate of infection in winter, salmonella in
summer and Campylobacter in spring (Kovats RS, et al..2005).
Relation between climate change and gastroenteritis.
The direct relation between the changes in climate and the increasing number of
gastroenteritis diseases are already proved by many researches done till now. (Kovats, RS, et al.,
2005), (Kovats RS, et al..2004). The transmission of the gastroenteritis causing pathogens is a
very important factor as the whole medication system is dependent mainly on the route of the
occurrances of the disease. (Haley et al., 2009).
The way of transmission of the bacteria can be in different ways. It can transmit through
foor, water, air and insects (Celik et al., 2015). The other most important way of transmission of

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gastroenteritis is the changes in the climate weather pattern and climate change. Variability of
climate or weather change can influence the human health (Costello et al., 2009, & Willox et al.,
2015) not only by the causing gastroenteritis but also by causing many other health issues
involving like the diseases of the respiratory organs lings, heart and even the airways. Many
problems of liver and the disease like cholera occurs because of the consumption of
contaminated food and water. (Altizer et al., 2013, Bouzid et al., 2014, Epstein, 2001a). For the
transmission of the infectious disease, most essential components are a host (vector) an agent (or
pathogen) and a transmission medium (environment). (Epstein, 2001a). The occurrence of the
diseases through vectors is the most fatal causative agent as it becomes very difficult to control
the causative agents. The vectors can small insects like flies or it can be pests from the fields and
also from homes.
Relation in between climate change and distribution of pathogens.
Climate is a very important factor in the survival and distribution of the disease
pathogens. Normally in the unhealthy environment many insects can be found which are very
hard to find at the normal conditions this is because most of these vectors become active in the
unhealthy environmental conditions, so it can be said that the changes in climate are very much
responsible for the occurrances of diseases. (Epstein, 2001a, Wu et al., 2014). An example of this
is in the monsoon most of the people suffer from different infectious diseases. These diseases
occur because of contaminations in food and water and at the same time are caused because of
the increase in different disease causing insects. Many people suffer from viral fevers and it is
very contagious and spreads from one disease person to anther healthy person. The increase in
the number of rats and other such animals contaminate the food items stored in the store houses
and thus when people consume those foods are infected with the diseases (Hellberg & Chu,

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2016). According to Ostfeld and Brunner, 2015, Rodó et al., 2013, long-term changes in climate
or warming up of climate, tends in favor of the expansion of infectious diseases geographically.
More outbreaks of the disease in new places were results of the extreme weather events.
According to (Kuhn et al., 2005, Wu et al., 2014) the transmission and distribution of infectious
diseases seasonally are constrained by the weather conditions, climatic conditions influence the
intensity and timing of the epidemic. For example, in the winter season sometimes rainfall
happens in specific some geographical areas and in those places the people suffer from same
diseases. Due to this sudden change in weather bacteria which needs such climate to grow will
start to grow and people will get infected and if the disease is infectious then it spreads from one
person to another and people from a specific area will get infected. In this way epidemic diseases
and pandemic diseases occur (Alexander et al., 2013) Alteration in infectious disease contact
patterns of vector-human, host- human or human pathogen is due to changes in climatic patterns
which in turn affect the transmission of disease.
The pathogens responsible for the gastroenteritis have different characteristics and
reproductive cycles and even different methods of transmission, so the seasonal patterns for each
pathogen vary from each other. The propensity of human behavior towards food habits and
lifestyle changes like picnics or social gatherings may also be affected by the temperature
changes according to seasons, which brings changes in rainfall rate and humidity. According to
Akil, L., Ahmad, H. A., & Reddy, R. S. 2014 the prevalence of salmonellosis and the rise in the
temperature holds a strong positive relationship. As the global temperatures are in rise due to
global warming and an increase in extreme weather events such as cyclones, flood, In turn affect
the proliferation of the disease pathogens. Variabilities in temperature and impact on
gastroenteritis and their association draws more attention. The disease increases with the increase

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WHAT ARE THE EVIDENCES THAT GASTROENTERITIS OUTBREAK ARE
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in the temperature, as in such high temperatures the body metabolism sometimes do not able to
work properly. So the body systems get hampered and cannot work properly (Manser et al.,
2013). So it is very important to address the topic of association of gastroenteritis with climate
change as has great importance in public health and finding evidence in support of the main
research question will help in improving the public health.
This literature review examines and summarises the evidence on how climate changes are
associated with gastroenteritis. Many evidences are there which shows that the disease
gastroenteritis is very much dependent on the changes in climate and in the patterns of weather.
Rationale
The rationale behind doing this study is the increasing health effects due to the increase
in the changes in climate. The disease gastroenteritis is one of the major health issues due to the
changes in climate. This disease is increasing globally involving both the developed and the
under developed countries not only in Australia (Onozuka, 2014). The proper understanding of
the evidences on associating the disease gastroenteritis and the changes in climate must help in
the designing proper systems and pursue different interventions to reduce the occurrence of
gastroenteritis globally. Because of this disease, the death rate has increased than it was in the
past. So it has become very necessary to reduce the incidences of this disease and the occurrence
of death because of this disease otherwise in future this disease will take severe form and many
people will die (Wade et al., 2014). So to reduce the disease people must take much care about
the climate change and the weather patterns.

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WHAT ARE THE EVIDENCES THAT GASTROENTERITIS OUTBREAK ARE
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Aim
The aim of this study is to understand if there is any evidence to support the link between
the changes in climate and the gastroenteritis.
Objectives
The objective of doing this research is do a thorough literature review and to do the
summary the evidences that are already existing which link the changes in climate or changes in
weather and the gastroenteritis outbreaks or cases.
Methods
This research is completely a systematic study and a thorough research has been done for
doing this research work from the databases CINAHL, COCHRANE, EMBASE and MEDLINE.
While doing this research the keywords that were used for doing the searching are climate
change, greenhouse effect, gastroenteritis, diarrhoea, vomiting, food borne diseases, water borne
diseases and extreme weather conditions. So many papers were found involving these key words
but not all of them were relevant for this research work. The papers which were having proper
and relevant information for this paper work were used. If improper papers were used then the
results would not match according to the requirements of this research work.
The required resources
The resources that were used for doing this research work are mostly from the databases
and some knowledge were obtained from the library also.

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Results
From the CINAHL database, 6290 articles were found relevant to this research work.
From the database MEDLINE 3561 articles were found to meeting the requirements of this
research work. From the database EMBASE, the relevant number of articles were only 349 and 8
articles from COCHRANE were found to be relevant for the study. All of these papers involved
research works from different countries and thus the result obtained from these papers made our
work more easy in knowing about how the disease gastroenteritis is occurring worldwide.
Discussion
This study has identified the significant gastrointestinal disorders which are occurred
because of the changes in the climate. Most of the data that are involved in this study are
collected from the research works that are done by collecting primary data, so the data that are
used for this experiment are all correct and quite valuable. Many papers are there which included
the wet seasons and obviously the reasons why gastrointestinal diseases occur during the wet
seasons. Much evidences are also there which showed that not only in the wet seasons, but in the
dry seasons also the gastrointestinal disease occurs. Studies are also related about the different
bacteria which mainly cause the disease including Salmonella many other Enterobacters.
It is already proved evidently that the disease gastroenteritis is very much associated with
the consumption of water. The water safety plans provided by the World Health Organisation has
guided with some rules which can help the supplies of the water to effectively find the potential
risks associated with the drinking of the water and can also implement the preventive barriers
which can improve the safety of people drinking water (Guentchev et al., 2016). Long term
studies have shown that the drinking of contaminated water has very less risk of occurring of