Infectious diseases dynamics in growing/finishing pigs in Southern Brazil (2005-2016) / Dinâmica de ocorrência das doenças infecciosas em suínos nas fases de crescimento e terminação no sul do Brasil (2005-2016)

This study aimed to determine the frequency and distribution of infectious diseases diagnosed through necropsy examination and histopathological analysis in growing/finishing pigs along 12 years (2005-2016) in Southern Brazil. We evaluated 1906 anatomopathological exams of pigs at growing/finishing phases, of which the infectious diseases corresponded to 75.6% of the cases (1,441/1,906). Porcine circovirus type 2 (PCV2) infections were the most frequent, accounting for 51.3% of the cases (739/1,441) with a higher frequency from 2005 to 2007, characterizing an epidemic distribution, with a gradual decline after 2008. Infectious diseases affecting the respiratory system were the second major cause with 30.1% of the cases. Among these, necrotizing bronchiolitis caused by swine Influenza (15.1%, 218/1,441) and bacterial pneumonia (15%, 216/1,441) were the main conditions. Influenza was mostly diagnosed from 2010 to 2013, accounting for 43.1% (167/387) of the cases. After this period, both respiratory infectious diseases were endemic. Digestive system infectious diseases accounted for 10.5% of the diagnoses (151/1,441), with the following main conditions: Salmonella spp. enterocolitis (43.7%, 66/151), Lawsonia spp. proliferative enteropathy (41.7%, 63/151), and Brachyspira spp. colitis (14.6%, 22/151). The latter had a higher incidence from 2012 to 2014 with all cases detected in this period. Polyserositis and bacterial meningitis represented, respectively, 5.8% (84/1,441) and 2.3% (33/1,441) of the cases diagnosed, with a constant endemic character.(AU)

O objetivo deste estudo consistiu em determinar a frequência e a distribuição das doenças infecciosas diagnosticadas através de exame de necropsia e análise histopatológica em suínos nas fases de crescimento/terminação ao longo de 12 anos (2005-2016) no sul do Brasil. Foram avaliados 1906 laudos anatomopatológicos de suínos nas fases de crescimento/terminação, dos quais as doenças infecciosas corresponderam a 75,6% (1441/1906) do total. As infecções por circovírus suíno tipo 2 (PCV2) foram as mais frequentes, contabilizando 51,3% (739/1441) dos casos, com uma alta frequência de 2005 a 2007 caracterizando uma distribuição epidêmica neste período, e um declínio gradual após o ano de 2008. A segunda principal causa incluiu as doenças infecciosas que afetam o sistema respiratório (30,1% dos casos). Dentre essas, destacaram-se a influenza suína (15,1%; 218/1441) e pneumonias bacterianas (15%; 216/1441). O diagnóstico de influenza apresentou uma frequência elevada de 2010 a 2013, totalizando 43,1% (167/387) dos casos. Após este período, ambas doenças infecciosas respiratórias exibiram caráter endêmico. As doenças infecciosas do sistema digestório totalizaram 10,5% (151/1441) dos diagnósticos, com as seguintes principais condições: enterocolite por Salmonella spp. (43,7%; 66/151), enteropatia proliferativa por Lawsonia spp. (41,7%; 63/151) e colite por Brachyspira spp. (14,6%; 22/151). A colite por Brachyspira spp. apresentou uma alta incidência de 2012 a 2014 com todos os casos detectados no período. As polisserosites e meningites bacterianas representaram 5,8% (84/1441) e 2,3% (33/1441) dos casos diagnosticados, respectivamente, com um caráter endêmico constante.(AU)

Clinical Profile and Outcome of H1N1 Influenza Infection at a Tertiary Care Teaching Hospital.

Background: The 2009 flu outbreak in humans, knownas "swine influenza" or H1N1 influenza A, refers toinfluenza A due to a new H1N1 strain called SwineOrigin Influenza Virus A (S-OIV). Global pandemicswith high mortality and morbidity occur when avirulent new viral strain emerges. Aim and Objectives:To study demography, clinical profile and outcome ofH1N1 influenza infection at a tertiary care teachinghospital. Material and Methods: This was aprospective observational study conducted at theteaching hospital during six month period. It was a timest bound study over a period of six months (from 1 Julyth 2018 to 30 December 2018). All suspects with throatswab/nasal swab positive for influenza H1N1 virus byReverse Transcriptase Polymerase Chain Reaction(RT-PCR) with age more than 15 years were includedin the present study. Data were analysed for mean,percentage, standard deviation and Chi square test forquantitative data by using Microsoft Excel spreadsheet. Results: A total 60 patients were admitted withconfirmed diagnosis of H1N1 infection. Out of the 21(35%) were males and 39 (65%) were females,predominated by female gender (p=0.001). The meanage in male (46.14 ± 20.058) was relatively morecompared to female gender (36.33 ± 11.50). The malegender had more co-morbidities and risk factorscompared to female patients (p=0.01) and wasstatistically significant. Out of total 21 male patients 7patients died because of bilateral pneumonia and AcuteRespiratory Distress Syndrome (ARDS) and MultiOrgan Dysfunction (MOD) with case fatality rate of33.33%. Out of total 39 female patients 5 patients diedwith case fatality rate of 12.82%. Conclusion: Thepresent study highlighted the disease burdenassociated with H1N1 infection. The advancing age,male gender, associated co-morbidities and delayedpresentation were the risk factors for mortality inpresent cohort study of H1N1 patients. The communityawareness, early case detection and timelymanagement can reduce the disease burden at large

Specific sIgA antibodies against swine influenza virus H3N2 infection / 中国人兽共患病学报

To study different breed pigs reply the swine flu virus infections,specific antibody of sIgA secretion regularity of respiratory tract and the differences of sIgA antibody according to different antigen proteins were detected.A/swine/Nanjing/ 51/2010(H3N2) was intranasally infected pigs (1 × 107 TCID50/mL and 2 mL/pig),and then the nasal swab samples were collected at different time points within 21 days after infection.M1,NS1 and PB1 recombinant protein,respectively,were used to establish indirect ELISA method for detecting specific antibody of sIgA,and to analyze its secretion regularity.Results displayed that there was no significant difference among three kinds of recombinant protein in the whole test,characterizing by specificity sIgA antibody levels rising rapidly after 5 infection days and reaching peak at day 14,then began to decline.Among different varieties of pigs,sIgA antibody production of PB1 protein in Obama group was significantly higher than that in binary pigs at 14th and 21st day (P＜0.05).It had no significant difference between M1 group and the NS1 group (P＞0.05).This experiment preliminary explores the secretion regularity of specificity sIgA antibody after infected swine flu virus,which laid a foundation for further study of SIV mucosal antibody diagnostic reagents.

Study on immunogenicity of recombinant lentivirus expressing trimeric HA of swine H1 N1 influenza virus / 中国免疫学杂志

Objective:To evaluate the protective immunity by vaccination of BALB/c mice with rLV-HA-GCN4,a recombinant lentivirus expressing the trimeric HA of swine H1N1 influenza virus. Methods:The female mice were randomly divided into rLV-HA-GCN4,rLV-HA,LV and PBS groups. Mice were primed with plasmid and boosted with lentivirus by the administration of intramuscular thigh injections at an interval of two weeks. At day 28 post-prime immunization,mice were inoculated intranasally with 100TCID50 of swine H1N1 influenza virus in a 50 μl volume. The immune levels were assessed by the T lymphocyte transformation test, flow cytometry,indirect ELISA and the indexes of spleen and lung. Results:The spleen lymphocyte transformation rate was 0. 3±0. 11 in the rLV-HA-GCN4 group at day 14 post-boost immunization, showing a statistical significance ( P<0. 01 ) compared to the PBS group. Meanwhile,rLV-HA-GCN4 could cause T lymphocyte response mainly based on the Th1-type CD4+ T cells. The IgG antibody titer reached to 1:8 000 at day 14 post-boost immunization and approximately 1:7 000 at day 14 post challenge. After challenge,the spleen and lung indexes of rLV-HA-GCN4 group were significantly lower than those of PBS group (P<0. 05). The body weight of rLV-HA-GCN4 group demonstrated a slight decrease before 3 days post challenge and then a gradual increase compared to the LV and PBS groups (P<0. 05). Conclusion:rLV-HA-GCN4 can effectively induce cellular and humoral immune response in BALB/c mice against swine H1N1 influenza virus.

A novel M2e-multiple antigenic peptide providing heterologous protection in mice

Swine influenza viruses (SwIVs) cause considerable morbidity and mortality in domestic pigs, resulting in a significant economic burden. Moreover, pigs have been considered to be a possible mixing vessel in which novel strains loom. Here, we developed and evaluated a novel M2e-multiple antigenic peptide (M2e-MAP) as a supplemental antigen for inactivated H3N2 vaccine to provide cross-protection against two main subtypes of SwIVs, H1N1 and H3N2. The novel tetra-branched MAP was constructed by fusing four copies of M2e to one copy of foreign T helper cell epitopes. A high-yield reassortant H3N2 virus was generated by plasmid based reverse genetics. The efficacy of the novel H3N2 inactivated vaccines with or without M2e-MAP supplementation was evaluated in a mouse model. M2e-MAP conjugated vaccine induced strong antibody responses in mice. Complete protection against the heterologous swine H1N1 virus was observed in mice vaccinated with M2e-MAP combined vaccine. Moreover, this novel peptide confers protection against lethal challenge of A/Puerto Rico/8/34 (H1N1). Taken together, our results suggest the combined immunization of reassortant inactivated H3N2 vaccine and the novel M2e-MAP provided cross-protection against swine and human viruses and may serve as a promising approach for influenza vaccine development.

Protective effect of N-acetylcysteine on mice with acute lung injury in-duced by H9N2 swine influenza virus / 中国病理生理杂志

AIM:To investigate the effects of N-acetylcysteine (NAC) on acute lung injury induced by H9N2 swine influenza virus ( SIV) in mice.METHODS: BALB/c mice were used to establish the animal model of acute lung injury by nasal inoculation of H9N2 SIV.The mice were divided into control group (without SIV infection), H9N2 SIV group (inoculation of H9N2 SIV) and NAC group (inoculation of H9N2 SIV plus pretreatment with NAC).The pulmonary edema was evaluated by determining the lung wet weight /dry weight ( W/D) ratio.The pathological changes of the lung tis-sues were observed .The concontrations of TNF-α, IL-1βand IL-6 in bronchoalveolar lavage fluid ( BALF) were meas-ured.The virus titer, T-SOD activity, MPO activity and MDA content in the homogenate of the lung tissues were detected . RESULTS:Treatment with NAC decreased the morality of infected mice , and significantly prolonged the survival time of infected mice .The pathological changes of the lung tissues , the lung W/D ratio and the lung index were relieved when SIV infected the mice treated with NAC .Treatment with NAC significantly decreased the infiltration of inflammatory cells inclu-ding macrophages, lymphocytes and neutrophils in the BALF .The levels of TNF-α, IL-6, IL-1βand MDA and the activity of MPO were also decreased.Treatment with NAC also significantly increased the T-SOD activity.CONCLUSION: The protective effect of NAC on the acute lung injury mouse model is related to suppression of the oxidative stress and inflamma -tory responses .

Protective efficacy of a high-growth reassortant swine H3N2 inactivated vaccine constructed by reverse genetic manipulation

Novel reassortant H3N2 swine influenza viruses (SwIV) with the matrix gene from the 2009 H1N1 pandemic virus have been isolated in many countries as well as during outbreaks in multiple states in the United States, indicating that H3N2 SwIV might be a potential threat to public health. Since southern China is the world's largest producer of pigs, efficient vaccines should be developed to prevent pigs from acquiring H3N2 subtype SwIV infections, and thus limit the possibility of SwIV infection at agricultural fairs. In this study, a high-growth reassortant virus (GD/PR8) was generated by plasmid-based reverse genetics and tested as a candidate inactivated vaccine. The protective efficacy of this vaccine was evaluated in mice by challenging them with another H3N2 SwIV isolate [A/Swine/Heilongjiang/1/05 (H3N2) (HLJ/05)]. Prime and booster inoculation with GD/PR8 vaccine yielded high-titer serum hemagglutination inhibiting antibodies and IgG antibodies. Complete protection of mice against H3N2 SwIV was observed, with significantly reduced lung lesion and viral loads in vaccine-inoculated mice relative to mock-vaccinated controls. These results suggest that the GD/PR8 vaccine may serve as a promising candidate for rapid intervention of H3N2 SwIV outbreaks in China.

Neutrophils to lymphocyte ratio as a screening tool for swine influenza.

Background & objectives: During an outbreak of influenza like illness throat swab culture and virus isolation are done to identify causal virus, and it may cause a significant delay in diagnosis and isolation. There is a need to determine a sensitive laboratory parameter which could play a major role in identifying H1N1 infection among patients presenting with influenza like symptoms. We undertook this study to determine a laboratory parameter to identify swine influenza infection amoung patients presenting with influenza like symptoms while awaiting throat swab culture and virus isolation reports. Methods: This retrospective study was conducted on patients presenting to A.P TB and Chest Hospital, Hyderabad, with swine influenza symptoms during September-October 2009. They were divided into swine flu positive (SW+) and swine flu negative (SW-) groups, based on their throat swab culture reports and laboratory data. Neutrophils to lymphocyte (N/L) ratio was calculated for every patient and also mean N/L ratio for two groups. Mean WBC count was also noted for both groups. Results: There were 55 patients in each group. The WBC count in SW+ group varied from 3000 to 10600 cells/mm3 (mean 5714), while in SW- group it varied from 4500 to 14300 cells/mm3 (10252). The N/L ratio was less than two for 92.7 per cent of patients in SW+ group and for 3.63 per cent patients in SW- group. N/L ratio < 2 as an indicator for swine flu had a sensitivity of 92.7 per cent and specificity of 96.36 per cent. It has a positive predictive value of 96.22 per cent and a negative predictive value of 92.8 per cent. Interpretation & conclusions: N/L < 2 along with a decrease in WBC count can be used as a screening tool in patients presenting with influenza like symptoms, while awaiting throat swab culture reports for confirmation.

Influenza A H1N1 virus in Indian pigs & its genetic relatedness with pandemic human influenza A 2009 H1N1.

Background & objectives: With the emergence of a new reassortant influenza A H1N1 virus that caused the 2009 pandemic it was felt necessary that pigs should be closely monitored for early detection of any influenza virus infection. Therefore, we investigated disease outbreaks with clinical history suggestive for swine influenza reported to our laboratory by owners of affected pig farms in Uttar Pradesh. Methods: Detection of swine influenza A virus (SIV) was attempted by isolation in embryonated chicken eggs. Presence of virus was detected by haemagglutination (HA) test and RT-PCR for amplification of different gene segments, cloning and sequencing. BLAST analysis of sequence data, phylogenetic analysis and mutation analysis based on HA, NA and matrix genes was done. Results: SIV could be isolated from one farm and all eight gene segments amplified by RT-PCR. BLAST analysis of partial nucleotide sequences and phylogenetic analysis using nucleotide sequence of HA (601 nt), NA (671 nt) and M (1031 nt) genes indicated close genetic relationship of the Indian swine isolate (A/Sw/UP-India-IVRI01/2009) with human pandemic 2009 (H1N1). The HA gene showed close relationship with the viruses of “North American Swine” lineage, whereas the NA and M genes clustered with the viruses of “Eurasian Swine” lineage, indicating a novel HA-NA reassortant. The remaining of 5 genes (NP, PA, PB1, PB2 and NS) belonged to “North American Swine” lineage. Interpretation & conclusions: This is perhaps the first report describing swine influenza among Indian pigs caused by an influenza A H1N1 virus sharing close homology with the human pandemic (H1N1) 2009 virus. Further reassortment with circulating influenza viruses must be closely monitored.

Current situation, clinical characteristics and management of human swine influenza A H1N1) in children / 国际儿科学杂志

Human swine influenza A (H1N1) is a highly transmissible infectious disease, which has spreaded globally and represented a continuous pandemic threat. The novel virus has predominantly affected the children and young adults. Clinical manifestations generally appear mild, but there are still many patients with severe complications leading to hospitalization. According to the current reports, the mortality in the early stages of the pandemic appears no more than seasonal influenza A . Children (especially less than 5years) are considered to be at higher risk of infection and complications. Pediatric patients with a underlying significant chronic disease such as chronic respiratory disease,cardiovascular disease and immunodeficiency disease, are at a higher risk of death. The neuraminidase inhibitors Oseltamivir and Zanamivir are effective for prophylaxis and treatment. Effective vaccines are regarded to be crucial for the control of influenza pandemics. This review focuses on the epidemiological situation, clinical characteristics and management of human swine influenza A (H1N1), so as to provide practical advice for clinicians.

Comparison of Rapid Antigen Test and Real-Time Reverse Transcriptase PCR for Diagnosing Novel Swine Influenza A (H1N1) / 대한임상미생물학회지

BACKGROUND: Novel swine influenza (H1N1) was first identified in Mexico in April 2009. Because of its high infectivity and worldwide distribution, a rapid and efficient screening test is necessary. Here we evaluated the usefulness of a rapid antigen test currently in use, compared to real-time RT-PCR (rRT-PCR) as a screening test for detection of novel swine influenza (H1N1). METHODS: A total of 1,228 patients who visited Hallym University Kangdong Sacred Heart Hospital with influenza-like illness between 14 August 2009 and 30 September 2009, and were tested by both rapid antigen and rRT-PCR tests, were enrolled in this study. RESULTS: Sensitivity, specificity, predictive value of a positive test, and predictive value of a negative test for the rapid antigen test were 30.5%, 99.2%, 86.4% and 90.1%, respectively. Fifty-one (4.2%) patients were positive for both rapid antigen test and rRT-PCR, and 1,053 (85.7%) were negative for both rapid antigen test and rRT-PCR. A total of 124 (10.1%) patients showed a discrepancy between the two tests. Among them, 116 (9.4%) were only positive for rRT-PCR and 8 (0.7%) were only positive for the rapid antigen test. The latter 8 patients all showed negative H1/M2 results in rRT-PCR. There were significant differences in detection rates of the rapid antigen test between different H1 Ct (threshold cycle) interval groups and for different age groups (P<0.05). CONCLUSION: Although the rapid antigen test is easy to perform and provides fast results, its limits as a screening test for detection of novel swine influenza (H1N1) due to its low sensitivity compared to rRT-PCR need to be considered in practical situations.

La pandemia y el pandemonio de la influenza A (H1N1) en el Perú / Pandemic H1N1 influenza and its pandemonium in Peru

Se presenta el desarrollo de la epidemia del virus influenza A (H1N1) en el país. La prense tuvo un papel importante en dar a conocer los alcances de la epidemia pero con su estilo alarmista contribuyó a crear una situación de incertidumbre, ya que esta epidemia se comportó como de intensidad leve a moderada. Las instituciones de salud pública se comportaron de acuerdo a las circunstancias y muchas veces pareció hacer eco de la prensa alarmista y de algunas sobreestimaciones en cuanto al verdadero impacto de la epidemia.

It is shown the development of the influenza A (H1N1) epidemics in our country. The mass media had an important role in to make known the extent of the epidemics but with its alarmist style contributed to create a state of uncertainty despite of the mild to moderate intensity of the epidemics. The public health institutions acted according to the circumstances and, many times, it seemed that they echoed the alarmist mass media and the overestimations of the real impact of the epidemics.

Avian Influenza and Swine Influenza:New Understanding of Crossing Species Barrier / 生物化学与生物物理进展

This year an outbreak of influenza in Mexico comes from a new epidemic of influenza viruses:A/H1N1 influenza virus.This virus is a kind of virus mixture,including human,avian and swine influenza virus gene fragments.The pathogenic mechanism of avian,swine and human influenza virus in its natural host were compared.The main purpose is to assess the risk of which pigs and poultry has the possibility to become one of zoonotic disease and to assess the possible role in process of avian flu transmission from pigs to people.As zoonotic disease,avian influenza and swine influenza virus have the key role in the process of human infection.But the influenza virus spread of crossing species barrier is not sufficient to cause a large outbreak of human influenza.Animal influenza viruses must have a significant genetic variation before they could live for a long term in the crowd.

Isolation and Genetic Characterization of H1N2 Subtype of Influenza A Virus from Pigs in Korea

In order to investigate swine influenza virus (SIV) infection in South Korea, 180 nasal swabs from pigs with respiratory symptoms of 18 different farms were collected between November 2001 and February 2002. Of the 180 swabs, 52 were positive for SIV by a multiplex reverse transcription-polymerase chain reaction (RT-PCR) assay. Positive samples were then subtyped by two multiplex RT-PCR assays, and 43 and 9 samples were found to be H1N2 and H3N2, respectively. SIV was isolated from the positive samples using embryonated chicken eggs. Two H1N2 isolates designated as A/Sw/ Korea/CY01/02 and A/Sw/Korea/CY02/02 were genetically characterized. Comparison of the nucleotide sequences between the two isolates showed 99.6% to 99.9% nucleotide identity of each gene segment. Pairwise sequence analysis of the hemagglutinin (HA)1 gene segments indicated that HA genes of the Korean isolates were more closely related to those of the US H1N2 isolates (94.5% to 97.9% amino acid identity) than those of the Japanese H1N2 isolates (82.4% to 93.7% amino acid identity). Amino acid sequences of the Korean isolate (A/Sw/Korea/CY02/02) showed high homology with the US H1N2 isolates; neuraminidase (NA) (97.4~99.2%), matrix (98.8~99.9%), nucleoprotein (97.6~ 98.0%), non-structural (96.8~98.6%), PA (97.9~98.7%), PB1 (98.3~99.6%) and PB2 (97.8~98.9%) genes.