The key difference between alternate host and collateral host is that alternate host is a host from a different family that helps to complete the life cycle of a pathogen, while the collateral host is a host from the same family of the main host that helps in the survival of the pathogen.
Disease management is an important study area in Pathology. To manage diseases, it is crucial to study aetiology, pathogenesis and epidemiology of them. Pathogens infect or survive in the host. So, this complex host-pathogen interaction is the key to control diseases. Usually, a pathogen uses a primary host. Also, alternate host and collateral host are two different types of hosts that sustain the pathogen. If a pathogen has an alternate host or collateral host, in disease management, it is vital to break or block the interaction between pathogen and these hosts. So, this article will help readers to understand the features of each and the difference between alternate host and collateral host.
CONTENTS
1. Overview and Key Difference
2. What is Alternate Host
3. What is Collateral Host
4. Similarities Between Alternate Host and Collateral Host
5. Side by Side Comparison – Alternate Host vs Collateral Host in Tabular Form
6. Summary
What is an Alternate Host?
An alternate host is a host that comes from a different family compared to the family of the main host. It helps the pathogen to complete its life cycle. Moreover, it supports pathogen for survival under unfavourable conditions. The malaria parasite Plasmodium uses two host organisms: mosquito and human being. Furthermore, liver fluke uses snails and sheep. Similarly, black fly lives on beans in summer and spindle bushes in winter. So, these are some examples of the interaction between pathogen and alternative hosts. Apart from the examples mentioned above, certain rust fungi are common examples of using alternative hosts to complete their life cycles. Barberry is an alternative host of Puccinia graminis tritici, wild or cultivated currant or gooseberry plants are alternative hosts of Cronartium ribicola and cedar is an alternate host of Gymnosporangium juniperi-virginianae.
Figure 01: Alternative Host – Barberry
Since an alternate host is essential to complete the life cycle of pathogen or parasite, control of alternative hosts is an effective way of reducing some diseases.
What is Collateral Host?
A collateral host is a host that belongs to the same family of the primary host. The particular host helps the pathogen to survive when the main host is not available. In simple words, pathogen survives in the collateral host during the offseasons of the main host.
Figure 02: Collateral host – Family Solanaceae
Fungal pathogens such as Alternaria solani and A. brassicicola mostly attack members of Solanaceae and Brassicae family, respectively, which are their collateral hosts.
What are the Similarities Between Alternate Host and Collateral Host?
- Alternate host and collateral hosts are two hosts other than the principal host on which a parasite can survive.
- Both types sustain the parasite under difficult conditions.
- Hence, control of alternative hosts is an effective way of controlling pathogens that cause diseases.
What is the Difference Between Alternate Host and Collateral Host?
The alternate host is a host that helps a pathogen to complete its life cycle. Here, the host belongs to a family different from the family of the main host. On the other hand, the collateral host is a host that helps pathogen to survive in the absence of the main host. But, this host belongs to the same family of the main host. So, this is the key difference between alternate host and collateral host.
The below infographic illustrates more facts such as examples, functions, etc., to support the difference between alternate host and collateral host.
Summary – Alternate Host vs Collateral Host
Pathogens usually use more than one host during their lifetime. Alternate host and collateral host are two kinds of hosts other than the main host that aid in the survival of the pathogen. Alternate host belongs to a family different from the family of the main host, while the collateral host belongs to the same family of the main host. So, this is the key difference between alternate host and collateral host.
Reference:
1. “Fundamentals of Plant Pathology.” Fundamentals of Plant Pathology: SURVIVAL, Available here.
Image Courtesy:
1. “3732810” (CC0) via Pixabay
2. “Illustration Solanum dulcamara0 clean” (Public Domain) via Commons Wikimedia