Superb Learning Destination Human health and Infectious diseases

 

Health is a state of complete physical, mental & social well-being. Health is affected by genetic disorders, Infections, change in life style (food, water, rest, exercise, habits etc).

Diseases may be Infectious or Non-infectious.

Pathogens: Disease (Infectious) causing organisms.  Parasites are pathogens as they harm the host by living in or on them.

COMMON INFECTIOUS DISEASES IN MAN

1. BACTERIAL DISEASES

a.    Typhoid: Pathogen is Salmonella typhi.

·   Mode of transmission: It enters the small intestine through food and water and migrates to other organs through blood.

·   Symptoms: Sustained high fever (39^o-40^o C), weakness, stomach pain, constipation, headache & loss of appetite. Intestinal perforation and death may occur.

Widal test is used for confirmation of the disease.

b.   Pneumonia: Pathogen is Streptococcus pneumonia & Haemophilus influenza.

·   Mode of transmission: Inhaling the droplets/aerosols released by an infected person. Sharing glasses and utensils with an infected person.

·   Symptoms: Infects lung alveoli. The alveoli get filled with fluid leading to respiratory problems. Fever, chills, cough, headache. Severe cases: Lips and finger nails turn gray to bluish colour.

2. VIRAL DISEASES

a.    Common cold: Pathogen isRhinoviruses.

·   Mode of transmission: Inhaling droplets resulting from cough or sneezes. Through contaminated objects.

·   Symptoms: Infects nose & respiratory passage. Nasal congestion and discharge, sore throat, hoarseness, cough, headache, tiredness etc. Last for 3-7 days.

3. PROTOZOAN DISEASES

a.    Malaria: Pathogen isPlasmodium sp. (P. vivax, P. malariae, and P. falciparum).

·   Mode of transmission: Anopheles mosquito biting.

·   Symptoms: Haemozoin causes chill and high fever recurring every 3-4 days.

Life cycle of Plasmodium

b.   Amoebiasis (Amoebic dysentery): Pathogen isEntamoeba histolytica.

·   Mode of transmission: Houseflies (mechanical carriers) transmit parasites from faeces to food & water.

·   Symptoms: Constipation, abdominal pain and cramps, stools with excess mucous and blood clots.

4. HELMINTH DISEASES

a.    Ascariasis: Pathogen isAscaris (Intestinal parasite).

·   Mode of transmission: Soil, water, vegetables, fruits etc. contaminated with faeces containing eggs of parasites.

·   Symptoms: Internal bleeding, muscular pain, fever, anaemia and blockage of intestinal passage.

b.   Filariasis (Elephantiasis): Pathogen isFilarial worms or Wuchereria (W. bancrofti & W. malayi).

·   Mode of transmission: Bite of female Culexmosquito.

·   Symptoms: Filarial worms live in lymphatic vessels (usually of lower limbs). It causes chronic inflammation of the organs in which they live for many years. Limbs and genital organs may be deformed.

5. FUNGAL DISEASES

a.    Ring worms: Pathogens are Microsporum, Trichophyton & Epidermophyton. They are seen in groin, b/w toes etc.

·   Mode of transmission: From soil or by using towels, cloths, comb etc. Heat and moisture help fungi to grow.

·   Symptoms: Appearance of dry, scaly lesions on various body parts such as skin nails and scalp. Intense itching.

Other infectious diseases

Bacterial Diseases

Disease	Pathogen	Transmission
Dysentery	Shigella	Contact, Contaminated food and water
Plague	Pasteurella pestis	Rat fleas
Diphtheria	Corynebacterium diphtheriae	Contaminated food, Direct contact
Cholera	Vibrio cholerae	Food & water contam-inated with faeces
Tuberculosis	Mycobacterium tuberculosis	Droplets from patient / carrier
Tetanus	Clostridium tetani	Contamination of wound by bacteria
Whooping cough	Bordetella pertussis	Contact, Droplets
Leprosy	Mycobacterium leprae	Direct contact
Anthrax	Bacillus anthrasis	Contact with cattle
Weil’s disease	Leptospira	Contact with rodents, dogs etc.

Viral Diseases

Disease	Pathogen	Transmission
Rabies	Rabies virus	Rabid dogs etc
Dengue	Dengue virus	Aedes mosquito
Influenza	Influenza virus	Coughing & sneezing
Measles	Rubeola virus	Droplets
German measles	Rubella virus	Close contact
Mumps	Mumps virus	Air borne droplets
Chicken pox	Varicella zoster	Air borne droplets
Small pox	Variola virus	Direct contact
Polio	Polio virus	Faeces & Air
Chikungunya	Chikungunya (CHIK) Virus	Aedes mosquito
Avian flu	H5N1 virus	Contact with infected poultry. Air borne spread
H1N1(Swine flu)	H1N1 virus	Contact with pigs, cough & sneeze of infected person.

PREVENTION AND CONTROL OF DISEASES

1.   Personal hygiene

Keep the body clean. Use clean drinking water, food etc.

2.   Public hygiene

a.    Proper disposal of wastes and excreta.

b.    Periodic cleaning and disinfection of water reservoirs, pools, cesspools and tanks.

c.    Avoid contact with infected persons or their belongings (to control air-borne diseases).

d.    Standard practices of hygiene in public catering.

e.    Control and eliminate the vectors (e.g. mosquitoes) and their breeding places.

-    Avoid stagnation of water.

-    Regular cleaning of household coolers.

-    Use of mosquito nets.

-    Introduce larvivorous fishes like Gambusia in ponds.

-    Spraying insecticides in ditches, drainage and swamps.

-    Doors and windows should be provided with wire mesh to prevent entry of mosquitoes.

These precautions can avoid vector borne diseases like Malaria, Filariasis, Dengue & Chikun gunya.