Lesson 10: Vector and Zoonoses Control & Air, Radiation, and Noise Pollution
Zoonosis
• Any infectious disease which animals can transmit to human beings
• Virchow (1855) used zoonosis as a synonym for infections by contagious animal poisons
• In general, pathogenic species responsible for zoonotic diseases can survive and multiply even without the presence of
man. So even without man these pathogenic species causing zoonosis can still live and multiply
• Can be caused by viruses, parasites, bacteria, and fungi
• In zoonotic diseases caused by parasites, the types of signs and symptoms can be different depending on the parasite
and the person
Types of Zoonosis
Reverse Zoonosis Emerging Zoonosis
• infectious disease of people occasionally transferred • zoonosis that is newly recognized or newly evolved
to animals and then transferred back to people or that has occurred previously but shows an
Examples: increase in incidence or expansion in geographical,
• Tuberculosis host, or vector range
• Mumps The recent emerging zoonoses example:
• Streptococcus pyogenes • Bird Flu
o (causes various infections to humans like • AIDS
tonsillitis, pharyngitis, cellulitis, and more ) • Mad Cow Disease
• Infectious Hepatitis • Nipah Virus
• Corynebacterium diphtheriae SARS-COV-2 (COVID-19)
Diphtheria that make toxin (poison)
Factors Influencing Emerging Zoonoses
• Change in Environment or environmental change
• Human and animal demography (statistics) like births and deaths
• Pathogen changes
• Changes in Farming practice
• Social and cultural factors such as food habits
• Actually viruses such as RNA viruses are among the most prominent examples of emerging pathogens because of their
ability to adapt quickly to changing environmental changes
Transmission Routes of Zoonotic Diseases
Aerosols • Occur when droplets are passed through the air from an infected animal and are breathed in by a
person
Ex. Soil contaminated with feces or urine and dust particles/droplets that contain the pathogen
Oral • A person can be infected orally by ingesting food or water contaminated with the pathogen
o Ex. Consuming animal products such as milk and meat not pasteurized and cooked properly
Eating or drinking after handling animals without washing hands
Direct coming into contact with the saliva, blood, urine, mucus, feces, or other body fluids of an infected animal
contact
Fomite • an inanimate object that can carry a pathogen from an animal to a person or from a person to
another
o Ex. door knobs, contaminated brushes, needles, clothes also like elevator buttons, light
switches. Commonly touched but rarely disinfected areas
o But in the case of zoonosis it can be clothes from animals like wool from sheep to make
clothes. If it's not treated or disinfected properly then maybe it can carry the pathogen and
infect humans.
Vector- • being bitten by a tick, or an insect like a mosquito or a flea carrying the infectious agent
borne • Ex. Dengue hemorrhagic fever transmitted by an infected mosquito
• Scientist estimates that more than 6 out of every 10 known infectious diseases in people can be spread by animals and
3 out of 4 new/emerging infectious diseases in people come from animals
• Zoonotic diseases are quite common
, (no need to memorize just to inform)
• 9 out of 10 leading causes of morbidity can be Zoonosis. Recently it has been suggested that Escherichia coli (E. Coli)
causing UTI may come from meat and animals as stated by a European Journal of Clinical Microbiology
• Also the Zoonotic type of TB as a form of tuberculosis in people caused by bacteria known as Mycobacterium Bovis
which belong to the Mycobacterium complex
• According to WHO cattles are the most important reservoir for Mycobacterium bovis in relation to zoonotic exposure
in humans
Worst Pandemics of Zoonotic Origin in the 20th and 21st Century
PANDEMIC CAUSES OTHER DESCRIPTION
1918 Flu Caused by H1N1 influenza virus an unusually deadly influenza pandemic lasting from January 1918
Pandemic believed to be of avian origin to December 1920 (almost 3yrs)
Infected: 500 million
Death toll: 17M-50M
Asian Flu of Influenza A subtype H2N2 or Asian Death toll: 2M (worldwide); also of avian origin
1957 Flu Virus
Hong Kong flu Influenza A (H3N2) virus Aka 1968 Flu Pandemic
(comprised of 2 genes from avian Death toll: 1M worldwide
influenza
HIV/ AIDS Type of chimpanzee in Central (1920-present); 75.7 M ppl have been infected w/ HIV since the
Pandemic Africa start of its epidemic until 2019
Death toll: 32M
*As of April 9, 2021 there have been 133 M confirmed cases worldwide w/ 2.8 M covid deaths. 76.2 M ppl recovered; 669 M vaccine
doses administered. (No need to memorize this)
Principles of Zoonoses Prevention, Control and Eradication
Prevention - inhibiting/hinder the introduction of a disease agent into an area, a specific population group/
individual. Inhibiting/ hindering from infecting a group of ppl.
Control efforts - consist of steps taken to reduce a disease problem to a tolerable level and maintain it at the level. It
already happened, so you just have to control it.
Eradication final step in a disease control program; consists of the complete elimination of a disease-producing agent
worldwide. Completely removing/ eliminating organism
*Prevention and control are sometimes referred to as primary prevention (aimed at maintaining a healthy population; preventing
occurrence of a disease) and secondary prevention (minimize damage after a disease occurred.)
-The basic principles of zoonoses prevention, control, and eradication programs are focused upon breaking the chain of
transmission at its epidemiologically weakest link. Main focus in preventing zoonoses is to break the chain of transmission
where at its weakest link.
-Three factors are involved: the reservoir, transmission from the reservoir to the susceptible hosts, and the susceptible hosts.
Zoonosis
• Any infectious disease which animals can transmit to human beings
• Virchow (1855) used zoonosis as a synonym for infections by contagious animal poisons
• In general, pathogenic species responsible for zoonotic diseases can survive and multiply even without the presence of
man. So even without man these pathogenic species causing zoonosis can still live and multiply
• Can be caused by viruses, parasites, bacteria, and fungi
• In zoonotic diseases caused by parasites, the types of signs and symptoms can be different depending on the parasite
and the person
Types of Zoonosis
Reverse Zoonosis Emerging Zoonosis
• infectious disease of people occasionally transferred • zoonosis that is newly recognized or newly evolved
to animals and then transferred back to people or that has occurred previously but shows an
Examples: increase in incidence or expansion in geographical,
• Tuberculosis host, or vector range
• Mumps The recent emerging zoonoses example:
• Streptococcus pyogenes • Bird Flu
o (causes various infections to humans like • AIDS
tonsillitis, pharyngitis, cellulitis, and more ) • Mad Cow Disease
• Infectious Hepatitis • Nipah Virus
• Corynebacterium diphtheriae SARS-COV-2 (COVID-19)
Diphtheria that make toxin (poison)
Factors Influencing Emerging Zoonoses
• Change in Environment or environmental change
• Human and animal demography (statistics) like births and deaths
• Pathogen changes
• Changes in Farming practice
• Social and cultural factors such as food habits
• Actually viruses such as RNA viruses are among the most prominent examples of emerging pathogens because of their
ability to adapt quickly to changing environmental changes
Transmission Routes of Zoonotic Diseases
Aerosols • Occur when droplets are passed through the air from an infected animal and are breathed in by a
person
Ex. Soil contaminated with feces or urine and dust particles/droplets that contain the pathogen
Oral • A person can be infected orally by ingesting food or water contaminated with the pathogen
o Ex. Consuming animal products such as milk and meat not pasteurized and cooked properly
Eating or drinking after handling animals without washing hands
Direct coming into contact with the saliva, blood, urine, mucus, feces, or other body fluids of an infected animal
contact
Fomite • an inanimate object that can carry a pathogen from an animal to a person or from a person to
another
o Ex. door knobs, contaminated brushes, needles, clothes also like elevator buttons, light
switches. Commonly touched but rarely disinfected areas
o But in the case of zoonosis it can be clothes from animals like wool from sheep to make
clothes. If it's not treated or disinfected properly then maybe it can carry the pathogen and
infect humans.
Vector- • being bitten by a tick, or an insect like a mosquito or a flea carrying the infectious agent
borne • Ex. Dengue hemorrhagic fever transmitted by an infected mosquito
• Scientist estimates that more than 6 out of every 10 known infectious diseases in people can be spread by animals and
3 out of 4 new/emerging infectious diseases in people come from animals
• Zoonotic diseases are quite common
, (no need to memorize just to inform)
• 9 out of 10 leading causes of morbidity can be Zoonosis. Recently it has been suggested that Escherichia coli (E. Coli)
causing UTI may come from meat and animals as stated by a European Journal of Clinical Microbiology
• Also the Zoonotic type of TB as a form of tuberculosis in people caused by bacteria known as Mycobacterium Bovis
which belong to the Mycobacterium complex
• According to WHO cattles are the most important reservoir for Mycobacterium bovis in relation to zoonotic exposure
in humans
Worst Pandemics of Zoonotic Origin in the 20th and 21st Century
PANDEMIC CAUSES OTHER DESCRIPTION
1918 Flu Caused by H1N1 influenza virus an unusually deadly influenza pandemic lasting from January 1918
Pandemic believed to be of avian origin to December 1920 (almost 3yrs)
Infected: 500 million
Death toll: 17M-50M
Asian Flu of Influenza A subtype H2N2 or Asian Death toll: 2M (worldwide); also of avian origin
1957 Flu Virus
Hong Kong flu Influenza A (H3N2) virus Aka 1968 Flu Pandemic
(comprised of 2 genes from avian Death toll: 1M worldwide
influenza
HIV/ AIDS Type of chimpanzee in Central (1920-present); 75.7 M ppl have been infected w/ HIV since the
Pandemic Africa start of its epidemic until 2019
Death toll: 32M
*As of April 9, 2021 there have been 133 M confirmed cases worldwide w/ 2.8 M covid deaths. 76.2 M ppl recovered; 669 M vaccine
doses administered. (No need to memorize this)
Principles of Zoonoses Prevention, Control and Eradication
Prevention - inhibiting/hinder the introduction of a disease agent into an area, a specific population group/
individual. Inhibiting/ hindering from infecting a group of ppl.
Control efforts - consist of steps taken to reduce a disease problem to a tolerable level and maintain it at the level. It
already happened, so you just have to control it.
Eradication final step in a disease control program; consists of the complete elimination of a disease-producing agent
worldwide. Completely removing/ eliminating organism
*Prevention and control are sometimes referred to as primary prevention (aimed at maintaining a healthy population; preventing
occurrence of a disease) and secondary prevention (minimize damage after a disease occurred.)
-The basic principles of zoonoses prevention, control, and eradication programs are focused upon breaking the chain of
transmission at its epidemiologically weakest link. Main focus in preventing zoonoses is to break the chain of transmission
where at its weakest link.
-Three factors are involved: the reservoir, transmission from the reservoir to the susceptible hosts, and the susceptible hosts.
