Tag: pathogen and their mode of transmission

The mosquitoes act as a vector and help in the transmission of several diseases. Dengue fever is transmitted by the biting of the Aedes mosquito and the malaria is transmitted by the biting of the female Anopheles mosquito. 

An allergen is a type of antigen which are non-infectious that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies. The production of allergens stimulates the release of IgE (immunoglobulin E) antibodies. These IgE antibodies bind to the allergens and then activates receptors of mast cells which triggers the release of inflammatory chemicals such as histamine. Hence, allergens induce disorders through secretion of IgE and histamine.

• Dracunculus medinensis or Guinea worm is a nematode that causes dracunculiasis( guinea worm disease).
  
• Usually, the disease has no initial symptoms. About one year later, there is a painful burning feeling as a blister forms, usually on the legs. The blister bursts as the worm then come out of the skin over a few weeks.
• this Disease has been eradicated and India was declared as guinea worm disease free country by WHO in 2000.
• Hence The parasite which has been recently eradicated from India is Dracunculus medinensis.
• So, the correct answer is 'Dracunculus medinensis '.

Many microbial agents can commonly move from an affected person to someone else in a variety of ways. Such disease-causing microbes can spread through the air. This occurs through the little droplets thrown out by an infected person who sneezes or coughs. Someone standing close by can breathe in these droplets, and the microbes get a chance to start a new infection. Examples of such diseases spread through the air are the common cold, pneumonia and tuberculosis. Obviously, the more crowded our living conditions are, the more likely it is that such airborne diseases will spread.

Brain fever is caused by virus and transmitted through Culex tritaeniorhynchus, female mosquitoes. Mosquitoes acquire virus, while taking blood meal and pass it to next healthy person. 
When Anopheles female mosquito bites a malaria patient then malarial parasite also enters in mosquito, while blood suction. Malarial parasite can grow in mosquito body and pass to another person, when mosquito bites. Dengue virus is transmitted due to mosquitoes, Aedes aegypti.  
Typhoid is caused by bacteria called as Salmonella typhi. It is water borne disease. Typhoid patient's feces show presence of Salmonella typhi. When such feces comes in contact with drinking water bodies then water gets polluted. Such, water if used for consumption then person gets infected with typhoid. Hence, typhoid is not transmitted by mosquito. 

Foodborne illness can be caused by pesticides or medicines in food and naturally toxic substances such as poisonous mushrooms or reef fish. Foodborne illnesses may result from the consumption of food contaminated by microbial pathogens, toxic chemicals or radioactive materials. The temperature range in which food-borne bacteria can grow is known as the danger zone. Food safety agencies, such as the United States' Food Safety and Inspection Service (FSIS), define the danger zone as roughly 4–5°C to 60 °C. The FSIS stipulates that potentially hazardous food should not be stored at temperatures in this range in order to prevent foodborne illness. The delay between consumption of a contaminated food and appearance of the first symptoms of illness is called the incubation period. This ranges from hours to days, depending on the agent, and on how much was consumed. 

Contamination of drinking water sources by sewage can occur from raw sewage overflow, septic tanks, leaking sewer lines, land application of sludge and partially treated waste water. Sewage is a complex mixture and can contain many types of contaminants. The greatest threats posed to water resources arise from contamination by bacteria, nitrates, metals, trace quantities of toxic materials, and salts. Seepage overflow into drinking water sources can cause disease from the ingestion of microorganisms such as E coli, Giardia, Cryptosporidium, Hepatitis A, and helminths. Septic tanks are enclosures that store and process wastes by bacterial decomposition. Badly constructed percolation systems may allow water to escape without proper treatment.This water may seep to the land surface, runoff into surface water or flow directly into the water table causing waterborne diseases like cholera, typhoid, diarrhoea etc.

Airborne diseases are caused by pathogenic microbes small enough to be discharged from an infected person via coughing, sneezing, laughing and close personal contact or aerosolization of the microbe. The discharged microbes remain suspended in the air on dust particles, respiratory and water droplets. Illness is caused when the microbe is inhaled or contacts mucus membranes or when secretions remaining on a surface are touched. Many common infections can spread by airborne transmission at least in some cases, including: anthrax (inhalational), chicken pox, influenza, measles, smallpox, and tuberculosis.