Some Important Microbial Human Beings

Pathogens - Disease - Method of spread - Notes

VIRUSES

• Poxvirus - Smallpox - Air bone - Serious disease now eradicated

• Paramyxovirus - Measles - Air bone and close contact - Child hood disease,; measles vaccine gives protection

• Paramyxovirus - Mumps - Air bone and close contact - Childhood disease

• Herpesvirus  - Chickenpox - Air bone and close contact - Child hood disease

• Picornavirus- Poliomyelitis (infantile paralysis) - Through food and water contaminated with faeces; droplets; and direct contact - No specific treatment; major outbreak sweeps the world every 11 years

• Variety of viruses - Common cold - Air bone - No specific treatment

• Arbovirus - Yellow fever - Bite of infected Aedes mosquito (biological method) - Serious disease; vaccine gives protection

• Rhabdovirus  - Hepatitis A (Infective hepatitis) - Through contaminated food , water and palm wine - Common cause of jaundice

• A DNA virus - Hepatitis B (Serum hepatitis) - Through infected blood and blood products given via transfusions and injections - Carriers help to spread the disease

• Retrovirus (human immunodeficiency virus or HIV) - Acquired immune deficiency syndrome or AIDS (infected people may not shoe signs of the disease for years, but can spread it to others) - Through sexual contact; blood transfusion; infected needles and injection syringes; and infected mother to unborn child - Virus attacks and destroys body defense (immune) system, making the person susceptible to all microbial infections and some cancers; eventual death

BACTERIA

• Vibrio cholerae - Cholera - Through food and water contaminated with faeces; flies and carriers important in causing God contamination - Vomiting and diarrhea cause dehydration of body leading to death unless fluid is given through the blood vessels

• Salmonella typhi - Typhoid - Same as for cholera - High fever followed lager by bloody diarrhoea due to intestinal ulcers; treated with antibiotics

• Shigella dysenteriae  - Bacteria dysentery - Same as for cholera - Abdominal pain and diarrhoea

• Salmonella sp. - Food poisoning - Mainly through infected meat, poultry, eggs and milk; also via food contaminated by faeces - Diarrhoea and vomiting usually subside in 2 to 4 days

• Clostridium tetani - Tetanus or lockjaw - Through soil, dust or faeces - Spines germinate and multiply rapidly in oxygen starved environment found in cuts and wounds

• Corynebacterium diphtheriae  - diphtheria - Air bone - Toxin causes tissue damage; vaccine gives protection

• Mycobacterium tuberculosis - Tuberculosis - Air bone ; drinking milk from infected cattle - Serious childhood disease; vaccine gives protection

• Bordetella pertussis - Whooping cough - Airborne - serious childhood disease vaccine gives protection

• Neissera gonorrhoeae - Gonorrhoea - Direct contact through sexual intercourse - Venereal disease

• Treponema pallidum - Syphillis - Same as for gonorrhea - Serious venereal disease; long incubation period

• Treponema pertenue - Yaws  - Direct skin contact , and through files - Common in children now eradicated

PROTOZOA

• Entamoeba histolytica - Amoebic dysentery - Through food and water contaminated with faeces containing amoebic cysts; flies act as carries between faeces and food - Diarrhoea and abdominal pains

• Trypanosoma gambiense - Sleeping sickness - Through bite of infected tsetse fly - Serious disease found only in tropical Africa; affects nervous system

• Plasmodium sp. - Malaria - Bote of infected anopheles mosquito - Diseases characterized by bouts of chills, fever and sweating

FUNGI

• Dermatophytes: filamentous fungi that grow on skin hair and nails  - (I) Tinea versicolor - Direct skin contact - A common type of body ringworm with yellow patches in chest, neck, face and back

(ii) Onu madu  - Direct skin contact - Characteristic rash mainly on groins and folds of buttocks

(iii) Athlete's foot - Direct skin contact - Itchy , smelly patches between toes