Clinical cystoisosporosis associated to porcine cytomegalovirus (PCMV, Suid herpesvirus 2 ) infection in fattening pigs

Abstract

Cystoisospora (syn. Isospora) suis is the causative agent of neonatal porcine coccidiosis and one of the main causes of diarrhoea in suckling piglets worldwide. Infection with porcine cytomegalovirus (PCMV, Suid herpesvirus 2) causes inclusion body rhinitis in pigs. In a Swiss pig herd (n=2 boars, 7 sows, 2 gilts, 18 finishing pigs, 30 fattening pigs, 54 suckling piglets), an outbreak of PCMV infection with high morbidity in all age categories, characterized by fever, anorexia, reduced general condition, respiratory signs and increased piglet mortality, was diagnosed by histopathology and molecular methods. Five fattening pigs (age~17weeks) additionally showed diarrhoea, not typical for PCMV infections, and one fattener had to be euthanized due to poor condition. Histopathologically, severe fibrinopurulent jejunoileitis with extensive atrophy and fusion of intestinal villi, loss of goblet cells and crypt abscesses associated to C. suis infection were present. In the liver, herpesvirus intranuclear inclusion bodies were observed and PCMV was confirmed by PCR/sequencing. No further infectious causes of diarrhoea (i.e. Rotavirus A; TGEV; PEDV; PCV-2; enterotoxigenic Escherichia coli or Lawsonia intracellularis) were detected in the euthanized fattener. Coproscopically, C. suis oocysts were identified in the faeces from further fatteners with diarrhoea. While C. suis usually produces disease only in suckling piglets, its association with severe intestinal lesions and diarrhoea in ~17-week-old fatteners was surprising. It is supposed that the underlying PCMV infection might have contributed to the presentation of clinical cystoisosporosis in fattening pigs. The interaction mechanisms between these two pathogens are unknown.

Frequent Occurrence of Simultaneous Infection with Multiple Rotaviruses in Swiss Pigs

“…For VP4, four different genotypes were found: P[13] was most frequent ( n = 5), followed by P[6] ( n = 4), P[7], and P[32] ( n = 2 for both). While P[13], P[6], and P[7] are also present in well-known porcine reference genomes, P[32] has so far only been described in pigs from Ireland, UK, Denmark, and Germany [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ].…”

“…It also requires perfect condition and visualization of the enteral morphology. In addition, other pathogens, such as Cystoisospora suis , may lead to shortened villi and may have influenced the result [ 40 ]. While we can exclude TGEV and PEDV, the availability of data concerning the presence of other pathogens was inconsistent between samples and was therefore not included.…”

Detection of Cystoisospora suis in faeces of suckling piglets – when and how? A comparison of methods

“…Older pigs are largely refractory to infection and excretion and diarrhoea are very unusual unless temporary immunosuppression occurs, e.g. in a case of acute viral infections, like in a herd of Swiss fatteners reported lately [ 14 ]. Sows usually show low shedding rates with few oocysts [ 15 ] which is in part supposedly due to acquired immunity, but also attributed to the pronounced age resistance in C. suis infections [ 12 ].…”