Viral Co-Infections of Warthogs in Namibia with African Swine Fever Virus and Porcine Parvovirus 1

Abstract

Understanding virus circulation in wild animals, particularly those that have contact with domestic animals, is crucial for disease management and control. In Africa, warthogs are known to be asymptomatic carriers of porcine pathogens; a recent study in Namibia has shown them to be positive for Porcine circovirus-2 (PCV-2). In this study, the same samples used for the PCV-2 investigation in Namibia were further screened for the presence of African swine fever virus (ASFV) and porcine parvovirus 1 (PPV1) by PCR. Of the 42 animals tested, 2 (4.8%) and 13 (31%) were positive for AFSV and PPV1, respectively. The two AFSV were also co-infected with PPV1. Combing the results of this study with the results of the previous PCV-2 investigation, four warthogs were shown to be co-infected with both PPV1 and PCV-2. Sequence and phylogenetic analysis revealed that the AFSV belonged to genotype (Ib) but were from different serogroups. Unexpectedly, the ASFVs from the warthogs were genetically distinct to those observed in an outbreak in the same region of Namibia that occurred less than fifteen months prior to the sampling of the warthogs. In fact, a stronger genetic relationship was observed between the warthog viruses and historical Namibian and South African ASFVs identified in 1980, 2004 and 2008. For the PPV1s, the closest relative to the Namibian PPV1 were viruses identified in wild boar in Romania in 2011. This study confirms that warthogs are carriers of porcine pathogens and the data should encourage further studies on larger populations of wild and domestic swine to more fully understand the epidemiology and transmission of viral pathogens from these species.

Evidence of coinfection of African swine fever virus genotype X and Porcine parvovirus type 3 at pig farms in the North Kivu province, Eastern Democratic Republic of Congo

“…The proportion of coinfections indicates that 25% of the pigs that tested positive for PPV3 were also positive for ASFV. These results corroborate with a previous study in South Kivu province, DRC [9] and China [16] where ASFV was found in pigs infected with PPV .This is further supported by reports of a survey on the Namibian warthog ecosystem showing a concurrent infection between ASFV and PPV type 1 (PPV1) [17]. High infection rates of ASFV and PPV3 were detected from Misisi and Goma territories, and this was mainly due to the increased displacement of pig breeders and their belongings from rural areas to towns as people ed heightened rebel insurgency in rural villages.…”

A Phylogeographic Analysis of Porcine Parvovirus 1 in Africa

“…Of the 351 samples screened by PCR in this study, 31 (8.8%) were positive for PPV1 [i.e., Burkina Faso ( n = 2; positivity ratio = 3.85%), Ivory Coast ( n = 7; positivity ratio = 12.96%), Kenya ( n = 1; positivity ratio = 11.11%), Mozambique ( n = 17; positivity ratio = 17.71%), Senegal ( n = 2; positivity ratio = 11.76%), Tanzania ( n = 2; positivity ratio = 1.63%)]. Additionally, 40 sequences previously obtained from Namibia (positivity ratio = 36.35%) and Nigeria (positivity ratio = 20.6%) were included in the study [ 14 , 15 , 16 ].…”

“…PPV1 nucleotide sequences spanning the same VP2 region obtained in the present study and originating from Europe, North and South America, and Asia were downloaded from GenBank (when the sampling country and date were available). In addition, sequences ( n = 40) from two African countries Namibia and Nigeria were included [ 14 , 15 , 16 ]. All the sequences were merged with the ones generated in the present study and aligned using MAFFT [ 17 ] and their quality was evaluated.…”

An Updated Review of Ornithodoros Ticks as Reservoirs of African Swine Fever in Sub-Saharan Africa and Madagascar

“…Zimbabwe has reported relatively few outbreaks of ASF, with the earliest report being in 1961, caused by a genotype VIII ASFV [ 48 ]. In the early 90s, some outbreaks were investigated and related to genotype I and XVII [ 65 ], and more recently, in 2015, genotype II ASFV emerged in domestic pigs in Mashonaland Central Province in northern Zimbabwe [ 66 ].…”

“…Initial typing efforts which confirmed genotype I in warthogs [ 47 ] and in domestic pig outbreaks in Windhoek in 1989 [ 65 ] appeared to support this. However, subsequent typing of the 2018 domestic pig outbreak strains viruses and those present in warthogs from the same region, 15 months after the outbreak, revealed that whilst genotype I viruses were present in both suid species, the strains detected in domestic pigs were distinct from those in wild suids [ 48 ].…”