Table 1.

Important infectious diseases of zebrafish. Facilities: mean annual prevalence in facilitates based on data from 2006–2018 (752 cases involving 10,121 fish). Transmission: H=horizontal, V = vertical or maternal. ND = not determined as diagnosis for mycobacterial infections were usually at genus level.

Pathogen or Disease	Facilities (%)	Pathology	Severity	Chronicity	Transmission	Impact
Pseudoloma	45	Neuritis, encephalitis, myositis, emaciation	Few within clinical disease	Chronic	V, H	Behavior, fecundity
Mycobacteriosis	37	Granulomas in various organs	Severe to subclinical: Depends on species	Subacute to chronic, Depends on species	V?, H	See below
M. chelonae	ND	Granulomas in coelomic organs	Often subclinical	Chronic	H	Cytokine expression
M. marinum	ND	Massive granulomatous inflammation in various organs	Severe	Subacute	H	High mortality, zoonotic
M. haemophilium	ND	Similar to M. marinum, with numerous bacteria in tissues	Severe	Chronic	H	High mortality over several months
Intestinal Carcinomas	16	Small cell carcinomas, many with epithelial hyperplasia & dysplasia	Moderate,	Chronic	H	Many with subclinical changes, compromise cancer and microbiome studies
Pseudocapillaria tomentosa	10	Emaciation. Severe enteritis	Severe	Chronic	H	Morbidity, microbiome alterations, promoter of intestinal cancer. Compromise diet, cancer and microbiome studies
Myxidium strasingeri	22	Minimal, parasite free in lumen of urinary tract	Minimal	Chronic	H, †	Probably minimal
Bacteria (non-acid fast)	9	Variable	Usually severe in a few fish	Acute	H	Unknown, fairly rare.
Edwardsiella ictaluri	< 1	Severe, necrotizing, systemic	Severe	Acute	H	Very high mortality

^†Likely involves an annelid alternate host.