Shrimp draft genome contains independent clusters of ancient and current endogenous viral elements (EVE) of the parvovirus IHHNV

Shrimp have the ability to accommodate viruses in long term, persistent infections without signs of disease. Endogenous viral elements (EVE) play a role in this process probably via production of negative-sense Piwi-interacting RNA (piRNA)-like fragments. These bind with Piwi proteins to dampen viral replication via the RNA interference (RNAi) pathway. We searched a draft genome of the giant tiger shrimp (Penaeus monodon)(GenBank record JABERT000000000) for the presence of EVE related to a shrimp parvovirus originally named infectious hypodermal and hematopoietic necrosis virus (IHHNV). The shrimp draft genome contained 3 piRNA-like gene clusters containing scrambled IHHNV EVE. Two clusters were located distant from one another in linkage group 35 (LG35). Both LG35 clusters contained multiple DNA fragments with high homology (99%) to GenBank records DQ228358 and EU675312 that were both called non-infectious IHHNV Type A (IHHNV-A) when originally discovered. However, our results and those from a recent Australian P. monodon genome assembly indicate that the relevant GenBank records for IHHNV-A are sequence-assembly artifacts derived from scrambled and fragmental IHHNV-EVE. Although the EVE in the two LG35 clusters showed high homology only to IHHNV-A, the clusters were separate and distinct with respect to the arrangement (i.e., order and reading direction) and proportional content of the IHHNV-A GenBank records. We conjecture that these 2 clusters may constitute independent allele-like clusters on a pair of homologous chromosomes. The third EVE cluster was found in linkage group 7 (LG7). It contained EVE with high homology (99%) only to GenBank record AF218266 with the potential to protect shrimp against infectious IHHNV. Our results suggested the possibility of viral-type specificity in EVE clusters. Specificity is important whole EVE clusters for one viral type would be transmitted to offspring as collective hereditary units. This would be advantageous if one or more of the EVE within the cluster were protective against disease caused by the cognate virus. It would also facilitate gene editing for removal of non-protective EVE clusters or for transfer of protective EVE clusters to genetically improve existing shrimp breeding stocks that might lack them.

Babesiosis

Babesia are intraerythrocytic, tick-transmitted, protozoan parasites that infect a broad range of wild and domesticated mammals including cattle, horses, dogs, and rodents. Human babesial infection is uncommon, mainly caused by B. microti in North America and B. divergens in Europe, with most infections occurring in asplenic people. Presentation is typically with non-specific ‘viral-type’ symptoms. Haemolytic anaemia is a characteristic feature and can be severe, particularly with B. divergens. Diagnosis is by discovering babesia organisms in Giemsa-stained blood smears, or detection of its DNA in blood by polymerase chain reaction. Aside from supportive care, treatment is usually with combinations of clindamycin and quinine or atovaquone and azithromycin. Mortality ranges from 5 to 40%. Prevention is by use of repellents, removing ticks from the skin, and avoidance of exposure in asplenic and immunocompromised individuals: there is no vaccine.

Frequency of Equus caballus papillomavirus in equine aural plaques

Despite the reported association between aural plaques and the presence of Equus caballus papillomavirus (EcPV), there are few data regarding the distribution of viral types in different geographic regions or possible correlations for different papillomaviruses and lesion characteristics. We detected the presence and frequency of EcPV (1–7) DNA in aural plaque biopsies of horses from different regions of Brazil and identified the patterns of these infections or coinfections and their possible association with lesion severity. A total of 108 aural plaque biopsies from horses in the 5 geopolitical regions of Brazil were examined. We performed PCR to detect EcPV DNA in the biopsies. At least 1 type of EcPV was detected in 97% of the samples. EcPV coinfection was observed in 59% of the samples. Compared to the other viruses, EcPV-4 was found at the highest frequency in coinfection (84%) or individually identified (32%). EcPV-2 and -7 were not detected. No significant association was found between lesion characteristics (type and distribution) and either the viral type detected or the presence of coinfection. EcPV is widely distributed in Brazil, both isolated and in coinfection; the viral type does not appear to influence the clinical characteristics of equine aural plaques.