Ichthyophthiriasis: emphases on the epizootiology

Abstract

Ichthyophthiriasis (white spot disease) is an economically important protozoosis caused by Ichthyophthirius multifiliis in freshwater fish. Medication prevention and curation are the main methods to control this disease with vaccines in laboratory, but the efficacy of drugs practically acts on the freeliving (nonparasitic) stage of I. multifiliis and can be easily impaired by a variety of environmental factors. Thus, study on the biological properties of I. multifiliis and the complicated ecological relationships between I. multifiliis and other biotic or abiotic factors that influence epidemicity of ichthyophthiriasis will contribute to integrated control of ichthyophthiriasis. In this article, some I. multifiliis biological properties, such as systematic position and life cycle of I. multifiliis, are briefly reviewed, and the seemingly abnormal phenomenon associated with in vitro cultures is specially discussed; then, the epizootiology of ichthyophthiriasis is emphasized, which involves various biotic or abiotic factors that impact the life and action of I. multifiliis. The susceptibility and stress reaction of fish to I. multifiliis infection are stated. Also, the pathogenicity and diagnosis of ichthyophthiriasis were covered, and an overall assessment is finally made on ichthyophthiriasis control.

Parasite Fauna of Tambaqui Reared in Net-Cages at Two Stocking Densities

“…Ichthyophthirius multifiliis is a ciliated protozoan that causes a great problem to farmed freshwater fish worldwide. This ciliate is often found on the tegument and gills of infected fish, and disease is highly contagious and can spreads rapidly from one fish to another, due to its direct life cycle (Wei et al, 2013;Wang et al, 2019).…”

The adenosinergic system, not the cholinergic system, exerts an anti-inflammatory profile in lymphatic immune organs of fish naturally infected with Ichthyophthirius multifiliis

“…Ichthyophthirius multifiliis is an important protozoan parasite of freshwater aquaculture worldwide, the etiologic agent of "white spot disease" or ichthyophthiriasis (Wei et al, 2013). This disease is characterized by severe skin and gill lesions, such as necrosis and ulcers, and intense inflammatory damage (Martins et al, 2015), resulting in high mortality and economic losses in species such as rainbow trout (Oncorhynchus mykiss) (Jorgensen et al, 2011), channel catfish (Ictalurus punctatus) (Burkat et al, 1990), common carp (Cyprinus carpio) (Gonzalez et al, 2007), Nile tilapia (Oreochromis niloticus) (Xu et al, 2008), zebrafish (Danio rerio) (Christoffersen et al, 2016) and silver catfish (Rhamdia quelen) (Santos et al, 2017).…”

Essential oils to control ichthyophthiriasis in pacu, Piaractus mesopotamicus (Holmberg): special emphasis on treatment with Melaleuca alternifolia

“…Considering the unfavourable conditions for the host during this study (average temperature of 19 °C, high initial parasitism and secondary infection), the results are considered promising. The average temperature of 19 °C is considered to be a risk factor for ichthyophthiriasis outbreaks (Wei, Li & Yu ), in addition to not being ideal for P. mesopotamicus , which prefers temperatures of 23–28 °C (Martinez, Azevedo & Winkaler ). The diagnosis of naturally occurring ichthyophthiriasis in group 4 (healthy fish) confirms this information.…”