Surreal illustration of alpacas and pigs in Peru with Echinococcus granulosus.

Echinococcus Granulosus: Unmasking the Threat in Alpacas and Pigs – What You Need to Know

"Discover how different strains of Echinococcus granulosus in alpacas and pigs in Peru highlight the need for targeted intervention programs and raise crucial public health questions."


Cystic echinococcosis (CE) is a parasitic disease caused by the tapeworm Echinococcus granulosus. This infection can affect both humans and various animal species. In Peru, CE is a significant concern, particularly in the central-southern regions known for cattle production. The prevalence of human CE cases in Peru is among the highest worldwide, underscoring the need for effective control measures.

Echinococcus granulosus exhibits intraspecific variations, leading to the classification into ten different strains or genotypes. These genotypes are associated with distinct intermediate host species. In Peru, the predominant genotype found in human cases is G1, the strain commonly associated with sheep. Additionally, the G1 genotype has been identified in cattle, sheep, and humans from endemic regions in Peru. In contrast, another study reported the presence of the G6 genotype (camel strain) in humans and goats, the G7 genotype in pigs, and the G1 genotype in sheep, cattle, pigs, goats, and humans in another endemic region.

The G7 genotype stands out due to its differences in morphology, development, and genetics compared to other strains. These differences impact its maturation rate and epidemiology. Recognizing the genotypes of Echinococcus granulosus present in livestock and wild animals within endemic regions is crucial for understanding the disease's spread and designing effective intervention programs. This article explores the genotypes circulating in alpacas and pigs in an endemic region of Peru, shedding light on the diversity of strains and their potential implications for public health.

How Does Genotype Diversity Impact Disease Transmission?

Surreal illustration of alpacas and pigs in Peru with Echinococcus granulosus.

A recent study investigated the genotypes of Echinococcus granulosus present in alpacas and pigs in the CE-endemic regions of Puno and Ayacucho, Peru. Researchers collected hydatid cysts from four alpacas and eight pigs post-slaughter in abattoirs. Genetic analysis was performed on these samples to determine the specific genotypes present.

The findings revealed that all the cysts collected from alpacas were fertile, indicating a high potential for transmission. In pigs, the fertility varied depending on the organ affected: all lung cysts were fertile, but only half of the liver cysts were fertile. This high percentage of fertile cysts in both alpacas and pigs suggests an elevated risk of transmission to other animals and humans in these regions.

  • G1 Genotype in Alpacas: All four alpaca isolates were identified as the G1 genotype, which is commonly associated with sheep. This is the first report of the G1 genotype in alpacas from CE-endemic regions in Peru.
  • G1 and G7 Genotypes in Pigs: The pig isolates showed more diversity. Four isolates were identified as the G1 genotype, while the remaining four were identified as the G7 genotype, also known as the pig strain.
  • Genetic Analysis: The genotypes were determined by analyzing two mitochondrial genes: cytochrome C oxidase subunit 1 (CO1) and NADH dehydrogenase subunit 1 (ND1). Polymerase chain reaction (PCR) amplification and DNA sequencing were used to identify the genetic makeup of the Echinococcus granulosus isolates.
These results highlight that alpacas in the study region are exclusively infected with the sheep strain (G1) of Echinococcus granulosus, while pigs can harbor either the sheep strain (G1) or the pig strain (G7). The presence of the G7 genotype in pigs from Ayacucho, an endemic region for CE in Peru, is noteworthy. Previously, the G7 genotype had only been identified in pigs from Lima, a city considered to be a low endemic area for CE.

Takeaways: The Importance of Continued Surveillance and Targeted Control

The findings from this study emphasize the need for continued surveillance and targeted control measures for cystic echinococcosis in Peru. The presence of different Echinococcus granulosus genotypes in alpacas and pigs highlights the complexity of disease transmission and the importance of understanding local strain dynamics. Further research is needed to determine the role of the pig strain (G7) in human disease in Peru and to develop effective strategies for preventing and controlling CE in both animals and humans.

About this Article -

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This article is based on research published under:

DOI-LINK: 10.1590/s0074-02762012000200019, Alternate LINK

Title: Echinococcus Granulosus Genotypes Circulating In Alpacas (Lama Pacos) And Pigs (Sus Scrofa) From An Endemic Region In Peru

Subject: Microbiology (medical)

Journal: Memórias do Instituto Oswaldo Cruz

Publisher: FapUNIFESP (SciELO)

Authors: Elizabeth Sánchez, Omar Cáceres, César Náquira, Eduardo Miranda, Franklyn Samudio, Octavio Fernandes

Published: 2012-03-01

Everything You Need To Know

1

What is cystic echinococcosis, and why is it a concern?

Cystic echinococcosis (CE) is a parasitic disease caused by the tapeworm Echinococcus granulosus. It affects both humans and animals. In Peru, it's a significant concern due to high human CE cases, especially in cattle-producing regions. Effective control measures are essential to combat its spread and impact.

2

What are Echinococcus granulosus genotypes, and why is it important to identify them?

Echinococcus granulosus has different strains, known as genotypes. The G1 genotype, typically linked to sheep, is common in human cases in Peru. The G7 genotype is different in morphology, development, and genetics. Knowing the specific genotypes in livestock and wild animals helps understand how the disease spreads, which is key for designing effective intervention programs. Identifying these genotypes is crucial for targeted control strategies.

3

How does the diversity of Echinococcus granulosus genotypes affect disease transmission?

Genotype diversity impacts disease transmission because different genotypes may have different host preferences, infectivity rates, or geographical distributions. For example, in Peru, alpacas were found to be infected exclusively with the G1 genotype, while pigs harbored both the G1 and G7 genotypes. Understanding these variations is crucial for predicting disease spread and implementing targeted control measures.

4

What did the study find about Echinococcus granulosus genotypes in alpacas and pigs in Peru?

The study identified the G1 genotype in alpacas for the first time in CE-endemic regions of Peru, indicating alpacas are infected with the sheep strain. In pigs, both G1 and G7 genotypes were found, showing pigs can harbor either strain. This means that control measures need to consider both the sheep strain and the pig strain when targeting CE in livestock.

5

Why are continued surveillance and targeted control measures necessary for cystic echinococcosis?

Continued surveillance and targeted control are crucial due to the presence of different Echinococcus granulosus genotypes in animals like alpacas and pigs. This highlights the complexity of disease transmission. Further research is needed to understand the role of the pig strain (G7) in human disease and to develop effective prevention and control strategies for both animals and humans.

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