A Review: Haemonchus contortus Infection in Pasture-Based Sheep Production Systems, with a Focus on the Pathogenesis of Anaemia and Changes in Haematological Parameters

Abstract

Haemonchosis is an important cause of anaemia in sheep worldwide, particularly those that are kept in pasture-based systems in warm, high rainfall environments. Potential outcomes vary based on the severity of infection and the sheep’s immune response, however, in some sheep infection can lead to death. The consequences of Haemonchus contortus infection mean that it has been well-studied in a range of different farming systems. However, to our knowledge, there has not been a recent review focused on the pathophysiology of anaemia caused by haemonchosis. Thus, this review provides an in-depth discussion of the literature related to the pathophysiology of haemonchosis and associated clinical signs for hyperacute, acute, and chronic haemonchosis. Additionally, haematological and biochemical findings are presented, and various diagnostic methods are assessed.

Arthrobotrys musiformis (Orbiliales) Kills Haemonchus contortus Infective Larvae (Trichostronylidae) through Its Predatory Activity and Its Fungal Culture Filtrates

“…Haemonchus contortus is one of the most pathogenic parasites responsible for significant damage to the health and productive potential of small ruminants [ 4 , 5 ]. This nematode is responsible for severe anaemia, hypoproteinaemia, oedema and diarrhoea, which can lead to death in young animals [ 6 , 7 ]. This and other genera/species of parasitic nematodes belonging to the group of gastrointestinal parasitic nematodes have an important economic impact in many countries.…”

Haemonchus contortus: an overview

“…H contortus disease prevalence is highest in tropical (southern India, central Africa and northern South America) and subtropical (Australia, southern Africa, southern North America and South America) zones. However, warm temperate zones such as seen in northern Europe have suitable conditions in wet summers and autumns for larval survival 2 …”

Diet‐microbiota crosstalk and immunity to helminth infection

“…11 In livestock, helminths are ubiquitous in pasture-based enterprises, and are generally considered to be the most significant health concern of sheep and goats worldwide, with diseases, such as haemonchosis threatening food security and sustainability of small ruminant farming. 12 Helminths are also a major concern in cattle, swine, and poultry production although the effects here are typically limited to sub-clinical infections that, none the less, can have a substantial impact on efficiency and profitability. 9 Notably, helminth infection has been shown to contribute significantly to greenhouse gas emissions from livestock, due to this reduced efficiency.…”