Infectious diseases are disorders caused by organisms — such as bacteria, viruses, fungi or parasites. Many organisms live in and on our bodies. They're normally harmless or even helpful. But under certain conditions, some organisms may cause disease.

Transmission is the passing of a pathogen causing communicable disease from an infected host individual or group to a particular individual or group, regardless of whether the other individual was previously infected.

Transmission can also be indirect, via another organism, either a vector (e.g. a mosquito or fly) or an intermediate host e.g. tapeworm in pigs can be transmitted to humans who ingest improperly cooked pork. Indirect transmission could involve zoonoses or, more typically, larger pathogens like macro parasites with more complex life cycles. Transmissions can be autochthonous i.e. between two individuals in the same place or may involve travel of the microorganism or the affected hosts.

Modes of  transmission

• Airborne transmission – very small dry and wet particles that stay in the air for long periods of time allowing airborne contamination even after the departure of the host. Particle size < 5 μm.
• Droplet transmission – small and usually wet particles that stay in the air for a short period of time. Contamination usually occurs in the presence of the host. Particle size > 5 μm.
• Direct physical contact – touching an infected individual, including sexual contact
• Indirect physical contact – usually by touching a contaminated surface, including soil.
• Fecal–oral transmission – usually from unwashed hands, contaminated food or water sources due to lack of sanitation and hygiene, an important transmission route in paediatrics, veterinary medicine and developing countries.

Airborne transmission

Airborne transmission refers to infectious agents that are spread via droplet nuclei (residue from evaporated droplets) containing infective microorganisms. These organisms can survive outside the body and remain suspended in the air for long periods of time. They infect others via the upper and lower respiratory tracts.
 

Droplet transmission

A common form of transmission is by way of respiratory droplets, generated by coughing, sneezing, or talking. Respiratory droplet transmission is the usual route for respiratory infections. Transmission can occur when respiratory droplets reach susceptible mucosal surfaces, such as in the eyes, nose or mouth.
 

Direct contact

Direct contact occurs through skin-to-skin contact, kissing, and sexual intercourse. Direct contact also refers to contact with soil or vegetation harbouring infectious organisms. Additionally, while  fecal–oral transmission is primarily considered an indirect contact route, direct contact can also result in transmission through feces.
 

Indirect contact

Indirect contact transmission, also known as vehicle borne transmission, involves transmission through contamination of inanimate objects. Vehicles that may indirectly transmit an infectious agent include food, water, biologic products such as blood, and fomites such as handkerchiefs, bedding, or surgical scalpels.

Fecal–oral

In the fecal-oral route, pathogens in fecal particles pass from one person to the mouth of another person. Although it is usually discussed as a route of transmission, it is actually a specification of the entry and exit portals of the pathogen, and can operate across several of the other routes of transmission.

Journal of infectious diseases and diagnosis announces papers for the upcoming issue. Interested can submit their manuscript through online portal

Submit manuscript at http://www.longdom.org/submissions/infectious-diseases-diagnosis.html or send as an e-mail attachment to the Editorial Office at editor.jidd@longdomjournal.org

Media contact:

Eliza Grace

Managing Editor

Journal of Infectious Diseases and Diagnosis

Mail ID: editor.jidd@longdomjournal.org