Microbio Emerging Disease

What is the causative organism of legionnaires disease?

Legionella pneumophila Gram negative, aerobic rod

Legionnaires disease mode of transmission

Vehicle – water droplets or aerosols

Found in lakes, air conditioners, whirlpool spas,

vegetable misters, & cooling towers.

Survives inside amoebas

Legionnaires disease signs and symptoms

Incubation period 2 to 10 days

High fever (40.5oC), chills, and dry cough

In advanced stages, diarrhea and nausea

Epidemiology of legionnaires disease

8,000 to 10,000 / year in US

Prevention of legionnaires disease

Water chlorination, cooling towers, showerheads

Distinctive features Of legionnaires disease

Mild pneumonia in healthy. Severe in elderly (15%

mortality)

Helicobacter pylori gastritis causative organism

Helicobacter pylori

• curved gram negative rod, polar flagella

Helicobacter pylori gastritis mode of transmission

• Fecal oral transmission

• Flies may transmit from feces

• Incidence increases with age

• Higher incidence in low income groups

Helicobacter pylori gastritis virulence factor

• Survive in stomach acid by producing urease

• Burrow into mucosa

Helicobacter pylori gastritis signs and symptoms

• Asymptomatic in 90%

• Peptic ulcers cause abdominal pain and bleeding

• Complication - stomach cancer

Helicobacter pylori gastritis treatment

Antibiotic combination

• inhibitor of stomach acid

Staphylococcal Toxic Shock Syndrome causative organism

Certain Staphylococcus aureus strains

Gram positive coccus

Staphylococcal Toxic Shock Syndrome Common mode of transmission

Introduction into vagina or a wound

Staphylococcal Toxic Shock Syndrome Virulence factor

Toxic shock syndrome toxins (TSS-1) -

superantigens

Staphylococcal Toxic Shock Syndrome Signs and symptoms

Fever, shock, multisystem organ failure, sunburn

rash

Staphylococcal Toxic Shock Syndrome Prevention

Avoid high absorbency tampons, change

frequently

•Tampons were classified as type II medical devices in 1980

Middle East respiratory syndrome causative organism

MERS-CoV , a corona virus SS RNA virus

Middle East respiratory syndrome transmission

Through respiratory secretions, coughs and sneezes

close contact

Infectivity index = 2

Middle East respiratory syndrome signs and symptoms

Fever, cough, shortness of breath

Middle East respiratory syndrome incubation period

5 to 6 days

Middle East respiratory syndrome virulence

Case fatality rate = 34%

Middle East respiratory syndrome prevention

Hand washing

Cover mouth and nose when sneezing

Disinfect fomites

COVID 19 causative organism

Severe acute respiratory corona virus- 2 virus

(SARS CoV-2) SS RNA virus

COVID 19 transmission

Respiratory secretions from talking, coughing, and sneezing

close contact

Asymptomatic patients can spread

Infectivity index = 2.2 to 3.2, Delta variant = >5, Omicron = 6.3

COVID 19 signs and symptoms

Asymptomatic or fever, dry cough, shortness of breath

In 20% of cases ‘long-Covid’

COVID 19 incubation period

2 to 14 days

COVID 19 virulence

Case fatality rate = 2%

COVID 19 prevention

Hand washing

Cover mouth and nose when sneezing

Disinfect fomites

Vaccines

What is a spillover infection?

A single event when a pathogen from one species moves into another species

◦ can result in an outbreak.

◦it may or may not be transmitted within the host population

Zika causative organism

Zika virus, genus Flavivirus, ssRNA

Zika Transmission

through the bite of an infected Aedes species mosquito

• from mother to child

• through sex

Zika Virulence factors

Attachment, fusion, invasion capabilities

Zika Incubation period

3 to 12 days

Zika signs and symptoms

• Fever, rash, joint pain

• Muscle pain, headache

• Birth defects – microcephaly

Zika treatment

Treat symptoms

Zika prevention

Avoid mosquito bites – repellents, nets

Mosquito control

Avoid sex with infected persons

Nipah causative organism

Nipah virus (NiV), genus Henipavirus, ssRNA virus

Nipah transmission

• Present in wild animal population and transmitted to domestic pigs

• Transmitted by infected pigs and bats to humans

• Drinking raw date palm sap contaminated by bats

Nipah incubation period

5 to 14 days

Nipah signs and symptoms

• Fever, headache, confusion

• Severe neurological conditions

Nipah treatment

Supportive care

Nipah prevention

• No vaccine

• Avoid exposure to pigs and bats

• Avoid raw date palm sap

Ebola and Marburg hemorrhagic fever causative organism

Ebolavirus or Marburgvirus - filoviruses

ssRNA virus

Ebola and Marburg hemorrhagic fever mode of transmission

Contact with bodily secretions of infected individual

(including semen) or via contact with bats

Ebola and Marburg hemorrhagic fever incubation period

Average of 8 to 12 days

Ebola and Marburg hemorrhagic fever virulence factors

Disruption of clotting factors

Ebola and Marburg hemorrhagic fever symptoms and signs

Fever, fatigue, headache, minor petechiae that progresses

to severe internal bleeding