The key difference between autoinfection and retroinfection is that autoinfection is a reinfection by a pathogen already present in the body while retroinfection is an infection that is contrary to the usual course.
Autoinfection and retroinfection are two modes of infections. In both types of infections, the infection takes place from the original host to itself. Therefore, both infections facilitate the pathogen to inhabit the same host indefinitely. They are two types of reinfections. Some pathogens use both types of infections as their mode of infections.
CONTENTS
1. Overview and Key Difference
2. What is an Autoinfection
3. What is a Retroinfection
4. Similarities Between Autoinfection and Retroinfection
5. Side by Side Comparison – Autoinfection vs Retroinfection in Tabular Form
6. Summary
What is an Autoinfection?
Autoinfection is a type of infection caused by a pathogen already present in the body. It is a type of infection which transfers from one part of the body to another part of the body. Chlamydia trachomitis is a pathogen which causes genital tract infections such as epididymitis and nongonococcal urethritis. Autoinfection from the genital tract to eyes can cause conjunctivitis.
Figure 01: Autoinfection
Enterobius vermicularis is a human pinworm that causes enterobiasis, which is an infection in men. Autoinfection is a mode of infection of E. vermicularis. Autoinfection happens when the patients scratch the perianal area and transfer eggs to mouth from contaminated hand. Eggs then hatch larvae and cause the infection in the small intestine. This is most common in children than adults. Strongyloides stercoralis is a threadworm which causes strongyloidiasis. Autoinfection of S. stercoralis involves the premature transformation of non-infective larvae into infective larvae which can penetrate the intestinal mucosa or the skin of the perineal area in order to cause infection again.
What is Retroinfection?
Retroinfection is a type of infection which is contrary to the usual course. Retroinfection is a mode of infection of Enterobius vermicularis. It happens from the eggs laid on the perianal skin. The eggs hatch larvae and they migrate through the anus to colon and initiate the infection. As a result of retroinfection, pathogen inhabits within the same host indefinitely. Moreover, retroinfection causes a very heavy parasitic load in the host. It ensures continued infestation as well. Most of the chronic infections in adults are mainly maintained by retroinfections.
What are the Similarities Between Autoinfection and Retroinfection?
- Autoinfection and retroinfection are two types of infection modes.
- Enterobius vermicularis infects via both autoinfection and retroinfection.
- In both infections, pathogen restarts or begins a new life cycle.
What is the Difference Between Autoinfection and Retroinfection?
Autoinfection is a type of reinfection which happens by the pathogen already present within the body. On the other hand, retroinfection is a type of infection which occurs due to the third stage larvae migrating back into the host. So, this is the key difference between autoinfection and retroinfection.
Moreover, generally, most o autoinfections occur from anus to mouth while most retroinfections occur from anus to colon. Also, autoinfections are more common in children than adults while retroinfections are more common in adults than children.
Below is a summary of the difference between autoinfection and retroinfection in tabular form.
Summary – Autoinfection vs Retroinfection
Autoinfection and retroinfection are two processes of reinfections. Autoinfection is a type of infection that happens from the pathogen already present in the body. Retroinfection is a type of infection which is contrary to the usual course. The third stage of larvae of pathogen migrates back to the host through the same route. Eggs that are hatched by pathogen transmitting primarily from anus to mouth of the host is a type of autoinfection. Eggs laid on the perianal skin hatch larvae and then larvae migrate back into the colon through the anus is a type of retroinfection. Thus, this is the key difference between autoinfection and retroinfection.
Reference:
1. Rawla, Prashanth. “Enterobius Vermicularis (Pinworm).” StatPearls [Internet]., U.S. National Library of Medicine, 8 Aug. 2020, Available here.
Image Courtesy:
1. “Strongyloides Stercoralis Life Cycle” By SuSanA Secretariat (CC BY 2.0) via Flickr