What is the Difference Between Fomite and Vector

The main difference between fomite and vector is that a fomite is a non-living object that transmits disease-causing pathogens, whereas vector is a living organism that transmits infectious organisms. Furthermore, a fomite takes part in indirect contact transmission while a vector takes part either in mechanical transmission or biological transmission. Some examples of fomites are pathogen-containing clothing, medical instrument, doorknobs, etc. while some examples of vectors include flies, mosquitoes, lice, etc. 

Fomite and vector are two modes of diseases transmission that occur through the spreading of infectious pathogens. Generally, many pathogens persist in a dormant stage in the outside environment and require a living host for the completion of their life cycle.  

Key Areas Covered 

1. What is a Fomite
     – Definition, Features, Types
2. What is a Vector
     – Definition, Features, Types
3. What are the Similarities Between Fomite and Vector
     – Outline of Common Features
4. What is the Difference Between Fomite and Vector
     – Comparison of Key Differences

Key Terms 

Biological Transmission, Disease Transmission, Fomite, Indirect Contact Transmission, Mechanical Transmission, Vector

What is a Fomite 

Fomite is a non-living object that can transmit a disease-causing pathogen to its host. Here, the method of transmission is through indirect contact. On the contrary, person-to-person transmission is the method of direct contact transmission. Furthermore, the non-living objects that serve as fomites may be contaminated with either individual or a reservoir of pathogens. For example, the droplets released by an infected individual with common cold through sneezing can land on a fomite such as a tablecloth. Then, the contact of this mucus by a susceptible host later can be infected. Therefore, this is a method of indirect contact transmission.

Figure 1: Surgical Instruments

Furthermore, the objects in clinical settings, including syringes, needles, catheters, and surgical equipment, are more prone to be contaminated with pathogens. Therefore, proper sterilization of these instruments ensures the control of microbial growth. 

What is a Vector 

A vector is a living organism, mostly an arthropod, that carries a disease-causing pathogen from one to another host. Basically, there can be two types of vector transmission. They are the mechanical and biological transmission. In the mechanical transmission, the vector that transmits the pathogen from one to another host is not infected by the pathogen. For example, flies that land on the faecal matter can come into contact with bacteria in the faeces. But later, they shed these bacteria to food when they land on it. Although these bacteria cause diseases, including diarrhoea, dysentery, etc. in humans, flies are not infected with bacteria.

Figure 2: Anopheles stephensi – Malarial vector

Moreover, in biological transmission, the vector responsible for the transmission is also infected by the disease-causing pathogen. Generally, most arthropods that serve as vectors bite the host, producing a wound, which in turn facilitates the entry of the pathogen into the host. Moreover, the saliva of these arthropods contains infectious particles produced by the pathogen inside its gut. Thus, pathogens to be transmitted into the host spend a part of their reproductive life cycle inside the vector. Therefore, the vector serves as the intermediate host, and it transmits pathogens to the definitive host.  

Furthermore, mosquitoes transmitting malaria, lice transmitting typhus, arachnids and ticks transmitting Lyme disease, mites transmitting scrub typhus, etc. are some examples of biological transmission of pathogens. Some mammals also serve as vectors by transmitting rabies to humans and chicken and other domestic poultry transmitting avian influenza to human. 

Similarities Between Fomite and Vector 

• Fomite and vector are two types of agents responsible for the transmission of disease-causing pathogens. 
• Generally, pathogens show adaptations to exploit host biology, behavior, and ecology to live in the host. 

Difference Between Fomite and Vector 

Definition 

Fomite refers to an object or material, which is likely to carry infection, such as clothes, utensils, and furniture, while vector refers to an organism, typically a biting insect or tick that transmits a disease or parasite from one animal or plant to another. 

Living or Non-Living 

Fomite is a non-living object, while vector is a living organism. 

Type of Transmission 

Fomite takes part in indirect contact transmission while vector takes part either in mechanical transmission or biological transmission.  

Examples: 

Some examples of fomites are contaminated clothing, medical instrument, doorknobs, etc. while some examples of vectors include flies, mosquitoes, lice, etc. 

Conclusion 

Fomite is a non-living object which can transmit disease-causing pathogens. Moreover, the transmission occurs through the indirect contact of contaminated clothing, medical instrument or other objects. On the other hand, a vector is a living organism that transmits pathogens. Moreover, the two methods of transmission are the mechanical and biological transmission. Therefore, the main difference between fomite and vector is the type of disease transmission. 

References:

1. “Modes of Disease Transmission.”ER Services | Microbiology, Lumen Candela, Available Here.

Image Courtesy:

1. “Surgical Instruments 01″By آرمین – Own work (CC0) via Commons Wikimedia   
2. “Anopheles stephensi”By Jim Gathany – This media comes from the Centers for Disease Control and Prevention’s Public Health Image Library (PHIL), with identification number #5814. (Public Domain) via Commons Wikimedia