Related Experiment Video
Updated: Jul 25, 2026

Raising the Mexican Tetra Astyanax mexicanus for Analysis of Post-larval Phenotypes and Whole-mount Immunohistochemistry
Published on: December 28, 2018
Aphanomyces astaci in Mexico: A new haplotype from dwarf crayfish Cambarellus montezumae
Laura Martín-Torrijos1, Ariadne Hernández-Pérez2, Jorge Francisco Monroy-López3
1Department of Mycology, Real Jardín Botánico-CSIC, Plaza Murillo 2, 28014 Madrid, Spain.
Abstract:
The crayfish plague is an emerging infectious disease caused by the pathogen Aphanomyces astaci (Oomycota), which is responsible for the decimation of Eurasian freshwater crayfish. This pathogen can coexist with the North American crayfish. These are chronic carriers of the disease as consequence of an immune response that can contain the growth of the pathogen without killing it. The origin of A. astaci locates in the southeastern United States and coincides with the origin of the family Cambaridae. This diverse family of decapods is distributed in North America from southern Canada to Honduras. However, only the native crayfish species from Canada and the USA have been examined for the presence of A. astaci. In this study, we describe for the first time the presence of A. astaci in Mexico in a population of the native species Cambarellus montezumae. By analyzing the small (rrnS) and large (rrnL) mitochondrial ribosomal regions, we showed the presence of two haplotypes of A. astaci within the same population (d1-haplotype and, a novel haplotype that was named, mex1-haplotype). The finding of A. astaci in Mexico confirms the occurrence of this pathogen within the range of the family Cambaridae. The individuals of C. montezumae appear to be chronic carriers of A. astaci, indicated by the lack of documented crayfish plague outbreaks in this population, similar to the pattern observed in other North American species. Thus, the results are of special concern to susceptible species of southern regions of America, i.e., Parastacidae. Therefore, this work emphasizes the need to better understand the distribution and genetic diversity of A. astaci within the distribution range of the natural carriers, i.e., North American species, especially the unexplored area of the family Cambaridae.
Insights
The crayfish plague pathogen Aphanomyces astaci was found in Mexico, carried by the native Cambarellus montezumae crayfish. This discovery highlights the need to study its distribution in North American crayfish species.
Area of Science:
- Aquatic Ecology
- Infectious Diseases
- Mycology
Background:
- Crayfish plague, caused by Aphanomyces astaci, devastates Eurasian crayfish populations.
- North American crayfish act as chronic carriers of A. astaci due to their immune response.
- The pathogen A. astaci originates in the southeastern United States, coinciding with the Cambaridae family's origin.
Purpose of the Study:
- To investigate the presence and genetic diversity of Aphanomyces astaci in Mexico.
- To determine if native Mexican crayfish species carry A. astaci.
- To assess the implications of A. astaci presence in Mexico for susceptible crayfish populations.
Main Methods:
- Analysis of the small (rrnS) and large (rrnL) mitochondrial ribosomal regions.
- DNA sequencing to identify A. astaci haplotypes.
- Field sampling of Cambarellus montezumae populations in Mexico.
Main Results:
- Aphanomyces astaci was detected for the first time in Mexico in Cambarellus montezumae.
- Two distinct A. astaci haplotypes were identified: d1-haplotype and a novel mex1-haplotype.
- C. montezumae individuals appear to be chronic carriers, showing no signs of crayfish plague outbreaks.
Conclusions:
- The presence of A. astaci in Mexico confirms its distribution within the Cambaridae family's range.
- The findings raise concerns for susceptible crayfish species in southern America (e.g., Parastacidae).
- Further research is crucial to understand A. astaci's distribution and genetic diversity in North American carrier species, particularly in unexplored regions.
Related Concept Videos
Migration
Bacterial Phylum Planctomycetes
Bacterial Phylum Actinobacteria
Bacterial Phylum Tenericutes
Fungal Phylum Ascomycota

