Focus on Environment

<strong>Focus</strong> Environ (2016)
Environment and Its Impact on Human Health
linked to various adverse health outcomes,
especially in people with pre-existing
medical conditions. Such controlled human
exposure studies might also enable a better
understanding of the underlying mechanisms
leading to possible adverse outcomes.
Ambient air contains many pollutants,
including gases such as ozone, oxides of
nitrogen, and Sulphur dioxide along with
particles of different sizes. Because of the
complexity of the composition of air
pollutants and the difficulty of precisely
measuring exposure, identifying the role of
different pollutants in respiratory morbidity
is no simple task. Among the various
pollutants, particulate matter with an
aerodynamic diameter of less than 2·5 μm
(PM2·5) have received a lot of attention
recently (Lim et. al., 2012). These small
particles are able to penetrate deep into the
small airways, alveoli, and blood stream,
where they can lead to subsequent
inflammation and vasoconstriction. WHO
has estimated that PM2·5 contributes to
roughly 800000 premature deaths per year
globally (Shah et al., 2013).
INFECTIOUS DISEASES AND
ENVIRONMENT
Infectious diseases emerging throughout
history have included some of the most
feared plagues of the past. Several factors
contribute to the emergence of infectious
diseases (Table 3). New infections continue
to emerge today, while many of the old
plagues are with us still (Ameli, 2015) and
are considered as a global problem. As
demonstrated by influenza epidemics, under
suitable circumstances, a new infection first
appearing anywhere in the world could
traverse entire continents within days or
weeks. Examples of emerging diseases in
various parts of the world include
HIV/AIDS; classic cholera in South
America and Africa; cholera due to Vibrio
Sridevi et al
cholerae O139; Rift Valley fever; hantavirus
pulmonary syndrome; Lyme disease; and
haemolytic uremic syndrome, a foodborne
infection caused by.certain strains of
Escherichia coli (Kamarulzaman et al.,
2016).
Most emerging infections appear to
be caused by pathogens already present in
the environment, brought out of obscurity or
given a selective advantage by changing
conditions and afforded an opportunity to
infect new host populations (on rare
occasions), a new variant may also evolve
and cause a new disease. The process by
which infectious agents may transfer from
animals to humans or disseminate from
isolated groups into new populations can be
called “microbial traffic”. A number of
human activity increase microbial traffic and
as a result promote the emergence and
epidemics. In some cases, including many of
the most novel infections, the agents are
zoonotic those transfer from their natural
hosts into the human population. In other
cases, pathogens already present in
geographically isolated populations are
given an opportunity to disseminate further.
Surprisingly often, disease emergence is
caused by human actions; however, natural
causes, such as changes in climate, can also
at times be responsible. Although this
discussion is confined largely to human
diseases, similar considerations apply to
emerging pathogens in other species.
Ecological interactions can be complex, with
several factors often working together or in
sequence. For example, population
movement from rural areas to cities can
spread a once-localized infection. The strain
on infrastructure in the overcrowded and
rapidly growing cities may disrupt or slow
public health measures, perhaps allowing the
establishment of the newly introduced
infection. Finally, the city may also provide
a gateway for further dissemination of the
infection. Most successful emerging
ISBN: 978-967-14475-0-5; eISBN: 978-967-14475-1-2 81