Dachrit Nilubol – PRRSControl

Avoid iatrogenic transmission of African Swine Fever and PRRS virus using Hipradermic®

Dachrit Nilubol — Mon, 05 Sep 2022 09:00:20 +0000

New publication in the International Pig Veterinary Society 2022 Evaluation of ASF and PRRS virus transmission between pigs when using conventional needle and needle-free device Introduction Porcine reproductive and respiratory syndrome (PRRS), a devastating disease in pigs characterized by respiratory and reproductive disease, has been present in Southeast Asia (SEA) since 90’s [1]. In addition to PRRS, the widespread of African swine fever (ASF) in this SEA region has increased a threat to ASF free herds [2]. Intramuscular administration using needles has been the main route of vaccination in pigs although, risks associated with conventional needles are high. PRRS virus (PRRSV), for instance, was transmitted by conventional needles and was able to induce the disease in naïve pigs [3]. Therefore, the objectives of this study were to evaluate African swine fever virus (ASF) and porcine reproductive and respiratory syndrome virus (PRRSV) transmission between conventional needle and needle-free device. Materials and Methods In the present study, forty-two, 3-week-old pigs were procured from a herd free of ASF and PRRSV. The negative statuses against both pathogens were confirmed by PCR in blood samples upon arrival. Eighteen pigs were randomly allocated into 6 groups called seeders of 3 pigs each including […]

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Is it safe to use two modified-live PRRSv vaccines on the same farm? Does it have any advantage?

Dachrit Nilubol — Tue, 01 Jun 2021 09:21:21 +0000

Some farms are using 2 different PRRS vaccines (EU-type and NA-type PRRS live vaccines) in 2-week intervals for gilt acclimation. Does this help maximize the immune level of gilts against PRRSv? If the pigs are exposed to more PRRSv, do they have a broad range of cross-protection? General aspects in PRRS live vaccine selection In general, the selection of PRRSV MLV used to control PRRS is based on the PRRSV species circulating in that particular region. For example, if a swine herd experiences a PRRSV-1 related outbreak, any available PRRSV-1 MLV can be used; while any PRRSV-2 MLVs can be used in a swine herd experiencing a PRRSV-2 related outbreak. This is because of heterologous protection, which is obviously observed in a field situation. These criteria for PRRSV vaccine selection are well accepted worldwide. Due to the fact that PRRSV species are genetically diverse, a homologous protection is obviously hard to confer. Sequencing data of the PRRSV isolates causing an outbreak is suggested and the genetic relationship between available MLV vaccines and isolates responsible for an outbreak should be considered. However, a problem occurs in a herd or in a region where both PRRSV-1 and PRRSV-2 are concurrently circulating. […]

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Can a PRRS vaccination affect the efficacy of other vaccines in sows and piglets?

Dachrit Nilubol — Thu, 15 Oct 2020 12:31:23 +0000

Immune suppression from PRRS vaccine: Can it differ based on the type of PRRS vaccine? Vaccination with PRRS MLV vaccine is like a field virus infection because the virus in the vaccine still has its natural ability to replicate in the host, shedding to in-contact pigs, and potentially suppress the host immune response by altering pro-inflammatory cytokine production, especially IL-10. Is IL-10 relevant for the PRRSV immune response? IL-10 functions as an immunosuppressive cytokine that can inhibit the host immune response. It is well established that IL-10 strongly inhibits cytokine production and proliferation fo CD4+ cells, in particular, the T helper cells (Th1), resulting in an inhibition of cell-mediated immune response. According to our previous published studies, we found that pigs vaccinated with different PRRS MLV vaccine, either PRRSV-1 or PRRSV-2, upregulates different level of IL-10 depending on the virus used for the PRRS vaccine manufacture, suggesting that immune suppression from PRRS MLV vaccine could be differed by different PRRSV MLV. Could this IL-10 up-regulation after the use of PRRS MLV vaccines interfere the efficacy of other piglet´s vaccines? Consequently, these findings of IL-10 up-regulation following PRRSV MLV vaccination and its suppressive property might be interfering with the […]

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What mortality level is to be expected in South-East Asia, in unvaccinated herds?

Dachrit Nilubol — Fri, 08 May 2020 06:27:57 +0000

With the strains of PRRSV currently circulating in South-East Asia, what mortality level is to be expected in an unvaccinated herd? Has the highly pathogenic PRRS virus epidemic burned out? Are the less virulent strains back? PRRSv diversity in South-East Asia Having more than 3,000 ORF5 gene sequencing data in my personal archive, both PRRSv-1 and PRRSv-2 are co-existing in all Thai swine herds. More than 10 herds in Vietnam, Cambodia, and the Philippines were tested, and both PRRSv types were found. Asian PRRSv-1 strains taxonomy For PRRSv-1, Thai isolates together with Vietnamese, Cambodian, and the Philippine isolates are mainly grouped in subtype 1, and further evolved into 3 clades including clades A, D and H (Stadejek et al., 2008). Asian PRRSv-2 strains taxonomy For PRRSv-2, Thai, Vietnamese, and Cambodian isolates are mainly grouped into 2 lineages including lineages 5, sublineage 5.1 and 8, sublineage 8.7 HP (Shi et al., 2010). Isolates in sublineage 8.7 HP are highly pathogenic (HP) PRRSv-2. Although isolates in sublineage 8.7 HP are still genetically related to their ancestral strains from China, disease severity has been less compared to that of the first emergence. PRRSv in the South-East Asia & Mortality […]

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Can we know the world distribution of PRRS disease? Have studies been carried out in Africa?

Dachrit Nilubol — Thu, 20 Dec 2018 12:12:14 +0000

PRRS disease is present in most of the pig producing countries, and especially in areas with a high pig density. There are, nonetheless, some countries that are PRRS-free, such as Australia, New Zealand, Switzerland, … To know more details you can visit chapter 6: “Geographical Distribution” of this site, where there is a summary regarding this matter. In order to have a more (theoretically) precise vision of the current global distribution of PRRS disease you can check OIE’s PRRS distribution map). However, attention must be paid to the PRRS status regarding several years, as certain countries can appear as «falsely» free of the disease due to the lack of the uploading of information concerning certain periods. With respect to Africa, specially: as far as I know, there are little data regarding the distribution of the PRRS infection in this continent. South Africa seems currently free of PRRS disease, even though it has repeatedly faced the introduction of PRRS virus in its territory (the outbreaks have been eradicated every time). See the World Trade Organization website to obtain more information. In the case of the rest of the African countries I haven’t found any data except the information available on […]

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