Bovine highly pathogenic avian influenza virus stability and inactivation in the milk byproduct lactose.

A bovine isolate of highly pathogenic avian influenza H5N1 virus was stable for 14 days in a concentrated lactose solution at under refrigerated conditions. Heat or citric acid treatments successfully inactivated viruses in lactose. This study highlights the persistence of HPAIV in lactose and its efficient inactivation under industrial standards.

Development and optimization of sampling techniques for environmental samples from African swine fever virus-contaminated surfaces with no organic contaminants.

African swine fever (ASF) is a highly contagious diseases in domestic pigs and wild boars with up to 100% mortality. ASF virus (ASFV) is a causative agent responsible for ASF and highly resistant in environments, which creates a significant challenge for the control and eradication of the virus. Despite the geographical expansion of ASFV and international movement of products to sustain the swine production system, there is limited knowledge on the use of environmental samples to perform surveillance to prevent the introduction of ASFV into ASFV-free areas and for control of transmission in affected areas. Therefore, this study aimed to develop and optimize sampling techniques for environmental samples for ASFV detection. The stainless steel surfaces were contaminated with ASFV-infected blood, swabbed using different devices, and then processed through different techniques. The environmental samples were processed and tested using qPCR analysis. The results showed that the use of pre-moistened gauze surgical sponges, sweeping pads, and sponge sticks resulted in increased sensitivity, when compared to either dry sampling devices or Dacron swab. In particular, the combination of the sponge stick and the commercial nucleic acid preservative supported the best detection of ASFV DNA on the clean stainless steel surfaces evaluated. Pre-incubation for the short period of time and centrifugation at low speed were sufficient to provide satisfactory diagnostic sensitivity of ASFV detection using qPCR for environmental samples. Our findings contribute to the development of techniques for environmental samples for ASFV surveillance to prevent the introduction and dissemination of ASFV.

Pigs are highly susceptible to but do not transmit mink-derived highly pathogenic avian influenza virus H5N1 clade 2.3.4.4b.

ABSTRACTRapid evolution of highly pathogenic avian influenza viruses (HPAIVs) is driven by antigenic drift but also by reassortment, which might result in robust replication in and transmission to mammals. Recently, spillover of clade 2.3.4.4b HPAIV to mammals including humans, and their transmission between mammalian species has been reported. This study aimed to evaluate the pathogenicity and transmissibility of a mink-derived clade 2.3.4.4b H5N1 HPAIV isolate from Spain in pigs. Experimental infection caused interstitial pneumonia with necrotizing bronchiolitis with high titers of virus present in the lower respiratory tract and 100% seroconversion. Infected pigs shed limited amount of virus, and importantly, there was no transmission to contact pigs. Notably, critical mammalian-like adaptations such as PB2-E627 K and HA-Q222L emerged at low frequencies in principal-infected pigs. It is concluded that pigs are highly susceptible to infection with the mink-derived clade 2.3.4.4b H5N1 HPAIV and provide a favorable environment for HPAIV to acquire mammalian-like adaptations.

Immunization with Virus-Like Particle Vaccine Protects Rabbits against Hepatitis E-3 Virus Infection.

Here, rabbits were immunized with a virus-like particle (VLP) vaccine prepared by expressing 239 amino acids of the swine hepatitis E virus (HEV)-3 capsid protein using a baculovirus system. Thirty specific-pathogen-free rabbits were divided into five groups (negative and positive control and 10, 50, and 100 µg VLP-vaccinated). Positive control group rabbits showed viremia and fecal viral shedding, whereas rabbits vaccinated with 10 µg VLP showed transient fecal viral shedding, and rabbits vaccinated with 50 and 100 µg VLP did not show viremia or fecal viral shedding. Serum anti-HEV antibody titers increased in a dose-dependent manner. Anti-HEV antibody titers were significantly higher (p < 0.05) in 100 µg VLP-vaccinated rabbits than in the negative control rabbits at week 4. Anti-HEV antibody titers were significantly higher in 50 and 10 µg VLP-vaccinated rabbits than in the negative control rabbits at weeks 8 and 11, respectively. Serum IFN-γ and IL-12 levels were significantly higher (p < 0.01) in rabbits vaccinated with 50 and 100 µg VLP than in the negative control rabbits at weeks 4 and 6. Liver tissues of 50 and 100 µg VLP-vaccinated rabbits displayed significantly less (p < 0.05) fibrosis than those of the positive control rabbits. The prepared VLP vaccine demonstrated dose-dependent immunogenicity sufficient for inducing anti-HEV antibody production, thus protecting rabbits against swine HEV-3.

Induction of immunocontraceptive effects in both male and female mice immunized with GnRH vaccine.

BACKGROUND: Gonadotropin-releasing hormone (GnRH) plays a pivotal role in regulating the reproductive endocrine system. OBJECTIVE: An immunocontraception vaccine aimed at inhibiting the functions of GnRH is tested as a potential tool for controlling animal populations. METHODS: We developed a recombinant immunocontraceptive vaccine composed of GnRH-I and GnRH-II (GnRH I+II), which was conjugated with Salmonella typhimurium flagellin. Forty-eight BALB/c mice aged 4 weeks were divided into four groups (each group had n = 12): non-vaccinated male (NVM), non-vaccinated female (NVF), vaccinated male (VM), and vaccinated female (VF). Mice in the vaccinated groups were vaccinated twice by intramuscular injection at 0 and 2 weeks with 300 µg of the recombinant GnRH protein complex per mouse. Mice in the non-vaccinated groups were injected with saline and served as the unimmunized controls. Twenty-four pairs of male and female mice were mated for 10-12 weeks after initial immunization in four groups: 6 NVF × 6 NVM, 6 VF × 6 NVM, 6 NVF × 6 VM, and 6 VF × 6 VM. RESULTS: An increase (p < 0.001) in antibody titers in VM and VF mice was observed. The testosterone levels and the number of spermatocytes were lower (p < 0.001) in VM mice than those in the control mice. The progesterone levels and the number of corpora lutea were lower (p < 0.001) than those in the control mice. Mating results in both VM and VF mice confirmed a 60% reduction in pregnancy rates and offspring numbers. CONCLUSIONS: The recombinant GnRH vaccine can be used for birth control in both male and female animals.

Coding-Complete Genome Sequence of a Recombinant Human Norovirus Strain Identified as Subtype GII.p12_GII.3.

A human norovirus (HuNoV) strain was obtained from a patient with acute gastroenteritis, and its complete coding sequence was determined. The coding-complete viral genome, with three open reading frames, was 7,565 bp long, with a GC content of 49.9%. The genotype of the HuNoV strain obtained in this study was identified as GII.p12_GII.3.

Identification of Hepatitis E Virus in Bovine and Porcine Raw Livers.

Several animal species including pigs are directly involved in the zoonotic transmission of the hepatitis E virus (HEV) to humans. This study was conducted to detect HEV in bovine and porcine raw livers by nested reverse transcription-polymerase chain reaction. Zoonotic HEV strains were identified in 1.0 and 3.0% of the tested bovine and porcine livers, respectively. HEV-4 was detected in the bovine livers, but both HEV-3 and HEV-4 were identified in the porcine livers. These results indicate that zoonotic transmission of HEV may occur via consumption of raw or undercooked livers of pigs and cattle.