Tuesday, April 24, 2007

MMic-Tutorials 1 to 4 (List of possible diseases)

A 85-year-old male was found to be staying alone in one-room flat. It is found that his mattress was soiled with human excreta and urine. The premise is infested with cockroaches, fleas and rats. It is known to the neighbors that the elderly man has the habit of feeding stray dogs and cats in the neighborhood.

The elderly man was referred to a nursing home and presented with high fever, rash and general weakness.

How would you approach this situation in order to provide final diagnosis of the suspected microorganism(s)?

The list of possible diseases:


1) African Trypanosomiasis
African trypanosomiasis is infection with protozoa of the genus Trypanosoma transmitted by the bite of a tsetse fly. Symptoms include characteristic skin lesions, intermittent fever and headache.

http://www.merck.com >
THE MERCK MANUAL > The Merck Manual of Diagnosis and Therapy> Infectious Disease > African Trypanosomiasis

2) Endemic Typhus (flea-borne typhus and murine typhus)
It is caused by Rickettsia typhi. It is transmitted by fleas that infest rats
. Less oftenly, it is caused by Rickettsia felis and is transmitted by fleas carried by cats. Symptoms include fever and weakness , followed by a rash.

http://en.wikipedia.org > Search > Endemic Typhus


1) Dengue fever
Dengue viruses are transmitted to humans through the bites of infective female Aedes
mosquitoes. Mosquitoes generally acquire the virus while feeding on the blood of an infected person. After virus incubation for 8-10 days, an infected mosquito is capable, during probing and blood feeding, of transmitting the virus, to susceptible individuals for the rest of its life.

> Media Center > Fact sheet > Dengue & Dengue Haemorrhagic Fever

2) Plague
The plague is an infectious disease due to a bacteria called Yersinia Pestis. Y. Pestis mainly infects rats and other rodents. Rodents are the prime reservoir for the bacteria. Fleas function as the prime vectors carrying the bacteria from one species to another. The fleas bite the rodents infected with Y. Pestis and then they bite people and so transmit the disease to them.

http://www.medterms.com > Search >Plague

Ming Boon

1) Rat-bite fever
Rat-bite fever is caused by either Streptobacillus moniliformis or Spirillum minus. Symptoms of the streptobacillary form include fever, rash, and arthralgias. The spirillary form causes relapsing fever, rash, and regional lymphadenitis.

http://www.merck.com > THE MERCK MANUAL > The Merck Manual of Diagnosis and Therapy> Infectious Disease > Spirochetes > Rat-bite Fever

2)Lassa fever
Lassa fever outbreaks have occurred in Nigeria, Liberia, and Sierra Leone. Cases have been imported to the US and the United Kingdom. The reservoir is Mastomys natalensis, a rat that commonly inhabits houses in Africa. Most human cases probably result from contamination of food with rodent urine. Symptoms begin with gradually progressive fever, weakness, rash.

http://www.tarakharper.com > Science > Lassa Fever

http://www.merck.com > THE MERCK MANUAL > The Merck Manual of Diagnosis and Therapy> Infectious Disease > Arboviridae, Arenaviridae, Bunyaviridae, and Filoviridae > Lassa Fever


1) Rocky mountain spotted fever
Disease is characterized by rashes and high fevers, usually contracted through insect bites. It is a bacteria with virus-like qualities.

http://www.bookrags.com >
Search >Rickettsia

2) Brucellosis
Brucellosis is a disease caused by bacteria in the genus Brucella. The primary complaints are are weakness and fatigue. An infected person may also experience muscle aches, fever, and chills.

http://www.bookrags.com >
Search> Brucellosis

Shahirah & Michelle

1) Toxoplasmosis
A single-celled parasite called Toxoplasma gondii causes a disease known as toxoplasmosis. A Toxoplasma infection can occur by accidentally swallowing cat feces from a Toxoplasma-infected cat that is shedding the organism in its feces.

http://www.cdc.gov > DPD Search > Toxoplasmosis > Fact Sheet

2) Leptospirosis
Leptospirosis is caused by a spirochaete bacterium called Leptospira interrogans. Symptoms include high fever and rash.

http://en.wikipedia.org > Search >Leptospirosis

3) Lyme disease
Lyme disease results from infection with Borrelia burgdorferi sensu lato complex. They are transmitted to humans through the bite of infected ticks.

http://en.wikipedia.org > Search> Lyme Disease

Symptoms include

  • A skin rash, often resembling a bulls-eye
  • Fever
  • Headache
  • Muscle pain
  • Stiff neck
  • Swelling of knees and other large joints
http://www.cdc.gov > Traveller's Health > Yellow Book > Chapter 4 – Prevention of Specific Infectious Diseases > Lyme Disease
http://medlineplus.gov > Search MedlinePlus > Lyme Disease > National Library of Medicine

4) General diseases caused by cockroaches
Cockroaches are capable of transmitting a long list of diseases. They are known carriers of:
  • Boils
  • Dysentary
  • Hepatitis
  • Plague
  • Salmonella
  • Typhus
http://www.sfenvironment.com/aboutus > Search > Cockroaches > SF Environment: Cockroaches

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