The most common zoonotic disease in the United States

Running head: MICROBIOLOGY
MICROBIOLOGY
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Introduction:
With the high prevalence of the chronic diseases, improvements in surveillance facilitated
better recognition of emerging zoonotic diseases around the globe. Zoonotic diseases are
considered as those infections which can be spread between animals and humans with or without
vectors. Nelson and Vincent (2015), highlighted that approximately 1500 pathogens cause
infection to human and 61% of these pathogens causes’ zoonotic diseases.Many researchers
reported that zoonotic diseases are most common in United States where more than 6 people out
of 10 people are experiencing infectious diseases which are spread from animals .(Loh et al.
2015). The most common zoonotic disease in the United States includes salmonellosis,
gastroenteritis, bird flu, giardiasis, and rabbis (Nolen et al. 2016). In the majority of the
cases, these infections spread through direct contact, indirect contact, vector-borne and food-
born. While anyone can be infected by zoonotic diseases, children younger than 5 years, adults
older than 65 and people with a weakened immune system are at high risk of developing diseases
(Pantin-Jackwood et al. 2017). Hence, this paper aimed to focus on one such zoonotic disease
such as bird flu where the causative agent is avian influenza (H5N1). This paper will provide an
overview of the pathogen and the disease it causes, an overview of live animal markets, the
environment around the market, the reason behind the association of animal market, risk,
biological factors, and control mechanism of the infection in following paragraphs.
Discussion:
Overview of pathogen:
Influenza type A viruses are of most significance to public health because of their
potential attributes for causing an influenza pandemic. Highly pathogenic influenza infection has

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been reported in domestic poultry of in 21 U.S. states from December 2014 to mid-June 2015.
(Www.cdc.gov 2019) While H5N1 mostly infect birds and transmission is mostly birds to birds,
a human who was in closed contact with the infected bird in the animal market most likely to
get infected by this influenza (Pei et al. 2018). This influenza A is only species
of Alphainfluenzavirus genus of the Orthomyxoviridae family of viruses (Kim,Webster and
Webby 2018). This orthomyxoviruses are negative-sense, single-stranded as well
as segmented RNA viruses and categorized based on their two protein present on the surface of
the viral envelop (Charu et al. 2017). Hemagglutinin is glycoprotein which is responsible for
viral attachment with the host cells. On the other hand, neuraminidase is an enzyme responsible
for the cleavage of Sialic acid from the glycoproteins and allows the virus to be released from the
host cell (Charu et al. 2017). In case of avian influenza, a type 5 hemagglutinin protein and a
type 1 neuraminidase protein together designed as H5N1 (Zhao et al. 2019). Influenza virus
constantly undergoes, genetic makeup and it has the ability to transmitted to the human very
easily. To gain access, the surface molecules in the virus must bind to the receptor on the
potential host cells. In birds as well as human lungs are highly prevalent in the receptors H5N1
virus which facilitates viral binding to the host cells (Zhao et al. 2019). When human is in close
contact with infected birds in the live animal market, they experience flu-like symptoms such as
cough, malaise sore throat, dysphonia, and muscle aches along with neurological changes in
advance stages. This change in the genetic makeup of influenza A viruses is due to “antigenic
shift.” Antigenic shift refers to the phenomenon when two different strains combined together to
give rise to new strain having a mixture of surface antigen ((Kim,Webster and Webby
2018). The changes can be observed due to antigenic drift where the accumulation of

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mutation observed within the genes that code antibody binding site (Kim,Webster and Webby
2018).
Overview of live market, pathogen association, and risk factors:
Chatziprodromido et al. (2015) conducted a systematic review in order to examine avian
influenza outbreaks and their distribution, in-between 2010-2016. Result of review
exhibited that avian influenza proved to contaminate different types of avian species such as
commercial poultry farms, wild birds, backyard domestic animals, mixed poultry and live
poultry. The crucial focus should be given on the wet market, slaughterhouses and live bird
market. Economic penalties of AIV in poultry are severe, as the infection affects the production
of eggs along with the quality of the egg and induces the high mortality in birds. Apart from the
United States, the geographic distribution of the flu includes Asian and African countries
(Www.who.int 2019). The high pandemic nature of the infection in Europe draws a close
relationship between spreading of virus and migration of wild birds across the globe. The world
health organization reported that the primary risk factors for developing an infection in human
are direct contact or indirect contact with live or dead poultry or contaminated environment
(Www.who.int 2019). Slaughtering, de-feathering mechanism, handling carcasses of diseased
poultry, as well as preparing poultry for consumption, particularly in domestic settings, are also
likely to be risk factors for developing an infection (Zhao et al. 2019). Hence, in order to control
the circulation of avian influenza through the live animal market like poultry farm, it is crucial
to implement proper hygiene, infection control procedure.
Risk of emergency, biological and social contributing factors behind the disease:
As discussed before, individuals who work in the live market, handle diseased poultry,
and weaken the immune system are at high risk of developing an infection. Hence, animal live