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1.
Lima; Instituto Nacional de Salud; ago. 2021.
Non-conventional in Spanish | LILACS, BRISA | ID: biblio-1354102

ABSTRACT

ANTECEDENTES: La enfermedad causada por el coronavirus de tipo 2 causante del síndrome respiratorio agudo severo (SARS-CoV-2) denominada como COVID-19 fue reportada inicialmente en la ciudad de Wuhan en China en diciembre de 2019 (1,3). Al poco tiempo, el 11 de marzo de 2020, fue caracterizada como pandemia por la Organización Mundial de la Salud (OMS). El espectro de la enfermedad es amplio e incluye desde cuadros leves y autolimitados hasta neumonía atípica severa y progresiva, falla multiorgánica y muerte (4,5). De acuerdo a la OMS, en el 2020 se subregistraron más de 1.8 millones de muertes a causa de esta enfermedad a nivel mundial. El Perú ha sido uno de los países más afectado en Latinoamérica con, al 30 de julio de 2021, más de 2 millones de casos y 196 214 fallecidos (letalidad de 9.31%) (6). Por lo tanto, conocer el tiempo de duración de esta inmunidad adquirida por la infección causada por SARS-CoV-2 es importante para poder guiar estrategias de vigilancia epidemiológica y de inmunizaciones. OBJETIVO: El objetivo de esta revisión fue identificar y sistematizar la evidencia disponible sobre el tiempo de permanencia de seropositividad y capacidad de neutralización de los Ac contra el SARS-CoV-2, la incidencia de reinfección y el tiempo hasta el evento en personas con antecedente de infección por SARS-CoV-2. METODOLOGÍA: Se realizó una revisión rápida basada en dos preguntas: En pacientes con antecedente de infección por SARS-CoV-2 ¿Cuál es el tiempo de permanencia de seropositividad y capacidad de neutralización de los Ac contra el SARS-CoV-2? ¿Cuál es la incidencia de reinfección y el tiempo hasta este evento? Se incluyeron estudios de cohorte. Para ello, se realizó una búsqueda sistemática en las bases de datos MEDLINE/PubMed, EMBASE/Ovid y LOVE/Epistemonikos. Luego de eliminar duplicados, los autores seleccionaron los ítems que cumplieran con las preguntas establecidas. RESULTADOS: Se incluyeron 32 estudios: 20 evaluaron el tiempo de permanencia de seropositividad de Ac anti SARS-CoV-2: 11 estudios evaluaron únicamente el tiempo de permanencia de seropositividad de los Ac, 9 estudiaron el tiempo de permanencia de seropositividad y capacidad de neutralización de los Ac, y 5 estudiaron únicamente el tiempo de permanencia de la capacidad de neutralización de los Ac 7 estudios evaluaron la incidencia de reinfección y el tiempo hasta este evento. La población incluida correspondió a adultos con antecedente de infección por SARS-CoV-2, 23 estudios incluyeron cohortes en población general, 6 incluyeron a personal de salud y 3 a donantes de plasma convaleciente. Para los estudios que evaluaron el tiempo de permanencia de seropositividad y capacidad de neutralización de los Ac, los periodos de observación fluctuaron entre 6 meses a 1 año. La mayoría (85%, 17/20) de los estudios coinciden en reportar la persistencia de Ac a los 6 meses de seguimiento, con variaciones en las frecuencias de las inmunoglobulinas (Ig) específicas (IgA, IgM, IgG) para las proteínas Spike (S), el complejo de unión al receptor (RBD) o a la proteína de nucleocápside (N). Los estudios reportaron que, hasta al menos 6 meses, la persistencia de la capacidad de neutralización de los Ac varió entre el 30.7 y 100% en los participantes. La incidencia de reinfección varió desde 0 a 4.85% en un tiempo aproximado de seguimiento de 180 días. De los 4 (57.14%) estudios que consideraron como intervalo de tiempo mínimo de 90 días en su definición de reinfección: la menor media de tiempo hasta la reinfección reportada fue de 116 ± 21 días y la mayor fue de 212 ± 25 días. Las personas que tuvieron una infección inicial por SARS-CoV-2 en comparación a aquellos sin infección previa (grupo control) tuvieron un menor riesgo de infección (reinfección), observándose una reducción de la incidencia de 84 a 89% en pacientes con infección previa en relación al grupo control; esta evidencia procede de 2 estudios. Hall et al., (41) realizó un sub-análisis de acuerdo a la presencia o no de síntomas de COVID-19 durante la infección inicial, reportando que el riesgo de reinfección en aquellos que fueron asintomáticos durante la infección inicial fue menor en comparación al grupo control (RTIa: 0.48, IC 95%: 0.37 ­ 0.63; reducción de riesgo relativo (RRR): 52%), aunque la reducción del riesgo fue mayor para el subgrupo con presencia de síntomas de COVID-19 en la infección inicial en comparación al grupo control (RTIa: 0.074, IC 95%: 0.06 ­ 0.10; RRR: 92.6%). La valoración de riesgos de sesgos indicó que los estudios que presentaron serias preocupaciones de riesgo de sesgos fueron el 65.75%: en los estudios sobre el tiempo de permanencia de seropositividad y capacidad de neutralización de los Ac anti-SARS-CoV-2, esta seria preocupación se presentó principalmente en el dominio 2 (sesgo de deserción) debido la pérdida de más del 60% de los participantes al final del seguimiento lo cual podría afectar la validez de los resultados. En los estudios sobre incidencia de reinfección, fue más frecuente (71.4%) la valoración de alguna preocupación de riesgo de sesgo debido a que el 71.4% fueron estudios retrospectivos y, en el 85.7% de los estudios las definiciones de reinfección no pudieron ser respaldadas por la realización de un análisis de secuenciación genómica. Las limitaciones de esta revisión son: que, debido a la heterogeneidad de las pruebas utilizadas para medir Ac, las definiciones de reinfección y la manera de reportar los desenlaces entre los diferentes estudios no fue posible realizar un meta-análisis para ninguno de los desenlaces. Adicionalmente, se incluyeron 8 (25%) estudios en pre-print y estos podrían modificar sus resultados y/o conclusiones en sucesivas versiones hasta su publicación, no siendo posible garantizar que respondan satisfactoriamente la revisión por pares y sean finalmente publicados. CONCLUSIONES: La evidencia disponible mostró que la mayoría (85%) de los estudios coinciden en reportar la persistencia de Ac a los 6 meses de seguimiento, con variaciones en las frecuencias de (Ig) específicas (IgA, IgM, IgG) para las proteínas S, RBD o a la proteína N. Hasta al menos 6 meses, la persistencia de la capacidad de neutralización de los Ac varió entre el 30.7 y 100% en los participantes. La incidencia de reinfección varió entre 0 a 4.85%, en un tiempo aproximado de seguimiento de 180 días. De los 4 (57.14%) estudios que consideraron como intervalo de tiempo mínimo de 90 días en su definición de reinfección: la menor media de tiempo hasta la reinfección reportada fue de 116 ± 21 días y la mayor fue de 212 ± 25 días. El antecedente de infección por SARS-CoV-2 redujo la incidencia de reinfección entre 84 y 89% en comparación a aquellos individuos sin infección previa (grupo control). La reducción de riesgo se mantuvo inclusive para el subgrupo de personas con infección inicial de tipo asintomática (reducción de incidencia de 52% en relación control); aunque, en menor magnitud que en aquellos que desarrollaron síntomas de COVID-19 (reducción incidencia de 93% en relación al control).


Subject(s)
Humans , Neutralization Tests/methods , Reinfection/immunology , SARS-CoV-2/immunology , COVID-19/immunology , Efficacy , Cost-Benefit Analysis
2.
Arq. Inst. Biol ; 88: e00802019, 2021. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1349009

ABSTRACT

The present research evaluated the seroprevalence of anti-zika virus (anti-ZIKV) antibodies by virus neutralization test (VNT) in 529 bovines from Andradina city, São Paulo state, Brazil. The reading was performed in an inverted optical microscope, considering reagents when the antibodies were capable to neutralize the ZIKV. Of the 529 samples, 53 (10.01%) were reagents. The animals were healthy at the time of collection. The samples were collected in February 2018, a favorable period for the multiplication of the vector and the highest risk of disease transmission. None of the animals showed anti-bovine viral diarrhea virus (anti-BVDV) antibodies, ruling out a possible cross-reaction, reinforcing the possible contact of the bovine with the ZIKV. In the herd, 88 pregnant females were evaluated; of these, 12 cows were reactive, with no history of reproductive problems or fetal malformations. This is the first research on the seroprevalence of ZIKV in cattle in Brazil, and studies should continue to evaluate cattle as a possible host of this arbovirus and its possible consequences for unique health and agribusiness.


Subject(s)
Animals , Cattle , Cattle , Seroepidemiologic Studies , Zika Virus , Antibodies , Viruses , Neutralization Tests , Flavivirus , Indicators and Reagents
3.
Article in English | WPRIM | ID: wpr-921355

ABSTRACT

Objective@#The coronavirus disease 2019 (COVID-19) pandemic continues to present a major challenge to public health. Vaccine development requires an understanding of the kinetics of neutralizing antibody (NAb) responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).@*Methods@#In total, 605 serum samples from 125 COVID-19 patients (from January 1 to March 14, 2020) varying in age, sex, severity of symptoms, and presence of underlying diseases were collected, and antibody titers were measured using a micro-neutralization assay with wild-type SARS-CoV-2.@*Results@#NAbs were detectable approximately 10 days post-onset (dpo) of symptoms and peaked at approximately 20 dpo. The NAb levels were slightly higher in young males and severe cases, while no significant difference was observed for the other classifications. In follow-up cases, the NAb titer had increased or stabilized in 18 cases, whereas it had decreased in 26 cases, and in one case NAbs were undetectable at the end of our observation. Although a decreasing trend in NAb titer was observed in many cases, the NAb level was generally still protective.@*Conclusion@#We demonstrated that NAb levels vary among all categories of COVID-19 patients. Long-term studies are needed to determine the longevity and protective efficiency of NAbs induced by SARS-CoV-2.


Subject(s)
Adult , Aged , Aged, 80 and over , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , Female , Humans , Kinetics , Male , Middle Aged , Neutralization Tests , SARS-CoV-2
4.
Medicina (B.Aires) ; 80(supl.3): 1-6, June 2020. ilus, graf, tab
Article in English | LILACS | ID: biblio-1135184

ABSTRACT

The disease named COVID-19, caused by the SARS-CoV-2 coronavirus, is currently generating a global pandemic. Vaccine development is no doubt the best long-term immunological approach, but in the current epidemiologic and health emergency there is a need for rapid and effective solutions. Convalescent plasma is the only antibody-based therapy available for COVID-19 patients to date. Equine polyclonal antibodies (EpAbs) put forward a sound alternative. The new generation of processed and purified EpAbs containing highly purified F(ab’)2 fragments demonstrated to be safe and well tolerated. EpAbs are easy to manufacture allowing a fast development and scaling up for a treatment. Based on these ideas, we present a new therapeutic product obtained after immunization of horses with the receptor-binding domain of the viral Spike glycoprotein. Our product shows around 50 times more potency in in vitro seroneutralization assays than the average of convalescent plasma. This result may allow us to test the safety and efficacy of this product in a phase 2/3 clinical trial to be conducted in July 2020 in the metropolitan area of Buenos Aires, Argentina.


La enfermedad denominada COVID-19 es causada por el coronavirus SARS-CoV-2 y es actualmente considerada una pandemia a nivel global. El desarrollo de vacunas es sin duda la mejor estrategia a largo plazo, pero debido a la emergencia sanitaria, existe una necesidad urgente de encontrar soluciones rápidas y efectivas para el tratamiento de la enfermedad. Hasta la fecha, el uso de plasma de convalecientes es la única inmunoterapia disponible para pacientes hospitalizados con COVID-19. El uso de anticuerpos policlonales equinos (EpAbs) es otra alternativa terapéutica interesante. La nueva generación de EpAbs incluyen el procesamiento y purificación de los mismos y la obtención de fragmentos F(ab’)2 con alta pureza y un excelente perfil de seguridad en humanos. Los EpAbs son fáciles de producir, lo cual permite el desarrollo rápido y la elaboración a gran escala de un producto terapéutico. En este trabajo mostramos el desarrollo de un suero terapéutico obtenido luego de la inmunización de caballos utilizando el receptor-binding domain de la glicoproteína Spike del virus. Nuestro producto mostró ser alrededor de 50 veces más potente en ensayos de seroneutralización in vitro que el promedio de los plasmas de convalecientes. Estos resultados nos permitirían testear la seguridad y eficacia de nuestro producto en ensayos clínicos de fase 2/3 a realizarse a partir de julio de 2020 en la zona metropolitana de Buenos Aires, Argentina.


Subject(s)
Humans , Animals , Immunoglobulin Fab Fragments/isolation & purification , Coronavirus Infections/therapy , Immune Sera/immunology , Antibodies, Viral/isolation & purification , Antibodies, Viral/immunology , Antibodies, Viral/chemistry , Argentina , Immunoglobulin G/isolation & purification , Immunoglobulin G/chemistry , Immunoglobulin Fab Fragments/chemistry , Neutralization Tests , Pandemics , Betacoronavirus , SARS-CoV-2 , COVID-19 , Horses
5.
Article in English | WPRIM | ID: wpr-763371

ABSTRACT

PURPOSE: Foot-and-mouth disease (FMD) and anthrax are important diseases in sheep. Vaccination is a favorable strategy against both infections. Simultaneous administration of vaccines does generally not impede the immune responses of each other, although there are some exceptions, and it may help reduce the labor and costs of vaccination as well as distress on animals. Although oil adjuvant FMD vaccine has been tried with live anthrax vaccine in cattle, there are no reports on the simultaneous use of both vaccines in sheep. MATERIALS AND METHODS: In this study, FMD seronegative sheep were used to investigate the impact of the simultaneous vaccination of FMD and anthrax on FMD antibody titers of sheep. Virus neutralization test and liquid phase blocking enzyme-linked immunosorbent assay were used to determine the antibody response to the FMD vaccine. RESULTS: The results demonstrated that both vaccines can be used simultaneously without any interference with the FMD response. Moreover, the simultaneous administration with anthrax vaccine had a stimulating effect on the early (day 7 post-vaccination) virus neutralization antibody response to the FMD vaccine. CONCLUSION: The simultaneous use of the FMD and anthrax vaccines did not hinder the response to the FMD vaccine in sheep.


Subject(s)
Animals , Anthrax Vaccines , Anthrax , Antibody Formation , Cattle , Enzyme-Linked Immunosorbent Assay , Foot-and-Mouth Disease , Neutralization Tests , Sheep , Vaccination , Vaccines
6.
Article in English | WPRIM | ID: wpr-742276

ABSTRACT

Arthropod-borne viruses (Arboviruses) are transmitted by arthropods such as Culicoides biting midges and cause abortion, stillbirth, and congenital malformation in ruminants, apparently leading to economic losses to farmers. To monitor the distribution of Culicoides and to determine their relationship with different environmental conditions (temperature, humidity, wind speed, and altitude of the farms) on 5 cattle farms, Culicoides were collected during summer season (May-September) in 2016 and 2017, and analyzed for identification of species and detection of arboviruses. About 35% of the Culicoides were collected in July and the collection rate increased with increase in temperature and humidity. The higher altitude where the farms were located, the more Culicoides were collected on inside than outside. In antigen test of Culicoides against 5 arboviruses, only Chuzan virus (CHUV) (2.63%) was detected in 2016. The Akabane virus (AKAV), CHUV, Ibaraki virus and Bovine ephemeral fever virus (BEFV) had a positive rate of less than 1.8% in 2017. In antigen test of bovine whole blood, AKAV (12.96%) and BEFV (0.96%) were positive in only one of the farms. As a result of serum neutralization test, antibodies against AKAV were generally measured in all the farms. These results suggest that vaccination before the season in which the Culicoides are active is probably best to prevent arbovirus infections.


Subject(s)
Agriculture , Altitude , Animals , Antibodies , Arbovirus Infections , Arboviruses , Arthropods , Cattle , Ceratopogonidae , Ephemeral Fever Virus, Bovine , Farmers , Humidity , Korea , Neutralization Tests , Palyam Virus , Ruminants , Seasons , Stillbirth , Vaccination , Wind
7.
Article in English | WPRIM | ID: wpr-742221

ABSTRACT

We developed a Rapid Diagnostic Test (RDT) kit for detecting IgG/IgM antibodies against Zika virus (ZIKV) using monoclonal antibodies to the envelope (E) and non-structural protein 1 (NS1) of ZIKV. These proteins were produced using baculovirus expression vector with Sf9 cells. Monoclonal antibodies J2G7 to NS1 and J5E1 to E protein were selected and conjugated with colloidal gold to produce the Zika IgG/IgM RDT kit (Zika RDT). Comparisons with ELISA, plaque reduction neutralization test (PRNT), and PCR were done to investigate the analytical sensitivity of Zika RDT, which resulted in 100% identical results. Sensitivity and specificity of Zika RDT in a field test was determined using positive and negative samples from Brazil and Korea. The diagnostic accuracy of Zika RDT was fairly high; sensitivity and specificity for IgG was 99.0 and 99.3%, respectively, while for IgM it was 96.7 and 98.7%, respectively. Cross reaction with dengue virus was evaluated using anti-Dengue Mixed Titer Performance Panel (PVD201), in which the Zika RDT showed cross-reactions with DENV in 16.7% and 5.6% in IgG and IgM, respectively. Cross reactions were not observed with West Nile, yellow fever, and hepatitis C virus infected sera. Zika RDT kit is very simple to use, rapid to assay, and very sensitive, and highly specific. Therefore, it would serve as a choice of method for point-of-care diagnosis and large scale surveys of ZIKV infection under clinical or field conditions worldwide in endemic areas.


Subject(s)
Antibodies , Antibodies, Monoclonal , Baculoviridae , Brazil , Cross Reactions , Dengue Virus , Diagnosis , Diagnostic Tests, Routine , Enzyme-Linked Immunosorbent Assay , Flavivirus , Gold Colloid , Hepacivirus , Immunoglobulin G , Immunoglobulin M , Korea , Methods , Neutralization Tests , Point-of-Care Systems , Polymerase Chain Reaction , Reagent Kits, Diagnostic , Sensitivity and Specificity , Sf9 Cells , Yellow Fever , Zika Virus
8.
Article in English | WPRIM | ID: wpr-739636

ABSTRACT

PURPOSE: The first aim of this study was to develop a novel inactivated porcine epidemic diarrhea virus (PEDV) vaccine using the recently isolated Korean PEDV QIAP1401 strain and to evaluate its protective efficacy in growing pigs. The second was to determine the optimum adjuvant formulation of the inactivated PEDV vaccine that induces protection against viral challenge. MATERIALS AND METHODS: To generate high titers of infectious PEDV, the QIAP1401 isolate was passaged in Vero cells. The experimental vaccines were prepared from a binary ethyleneimine-inactivated QIAP1401 strain passaged sequentially 70 times (QIAP1401-p70), formulated with four commercial adjuvants, and administered twice intramuscularly to growing pigs. Challenge studies using a virulent homologous strain of PEDV QIAP1401-p11, which was passaged 11 times after isolation, were performed to assess protection against disease progression and viral shedding during the 15-day observation period. The vaccine-induced antibody responses were measured in serum samples collected at predetermined time points by indirect enzyme-linked immunosorbent assay and virus neutralization test. RESULTS: The QIAP1401-p70 strain had 42 amino acid (aa) mutations, including a 25 aa deletion, and was selected as the inactivated PEDV vaccine candidate. Although none of the pigs that received the experimental vaccines were completely protected against subsequent viral challenge, they exhibited a significantly higher immune response than did non-vaccinated control pigs. Among the vaccine groups, the highest antibody responses were observed in the pigs that received an oil-based multiphasic water/oil/water (W/O/W) emulsion adjuvanted vaccine, which delayed the onset of clinical symptoms and viral shedding. CONCLUSION: A novel inactivated PEDV vaccine formulated with a W/O/W emulsion adjuvant was both immunogenic and protective against viral challenge.


Subject(s)
Antibody Formation , Disease Progression , Enzyme-Linked Immunosorbent Assay , Neutralization Tests , Porcine epidemic diarrhea virus , Swine , Vaccines , Vero Cells , Virus Shedding
9.
Article in English | WPRIM | ID: wpr-716736

ABSTRACT

Canine adenovirus type 2 (CAV-2) is the cause of a major respiratory illness in dogs. In this study, we analyzed adenovirus infections in dogs using 2000–2017 data from the Animal and Plant Quarantine Agency (APQA) and conducted a serological survey of CAV-2 infection in six animal species in Korea. In total, 38 of the 3,179 dog samples were confirmed as canine adenovirus infections. In serological survey, 1,028 dog sera, 160 raccoon dog sera, 100 cattle sera, 257 sow sera, 206 horse sera, and 106 cat sera, collected from January 2016 to July 2018, were screened for the presence of anti-CAV-2 antibodies by virus neutralization test. The seropositivity rates for dogs, raccoon dogs, cattle, sows, horses, and cats were 88.5% (910/1,028), 51.3% (82/160), 85.0% (85/100), 48.6% (125/257), 35.0% (72/206), and 2.8% (3/106), respectively. Among dogs and raccoon dogs, 1.9% (20/1,028) and 8.8% (14/160), respectively, had a virus-neutralizing antibody (VNA) titer of over 1:256. A high CAV-2 VNA titer indicates a repeated vaccination or natural infection in Korean dogs and circulation of CAV-2 in raccoon dog populations.


Subject(s)
Adenoviridae Infections , Adenoviruses, Canine , Animals , Antibodies , Cats , Cattle , Dogs , Horses , Incidence , Korea , Neutralization Tests , Plants , Quarantine , Raccoon Dogs , Vaccination
10.
Rev. biol. trop ; 65(1): 345-350, Jan.-Mar. 2017. tab
Article in English | LILACS | ID: biblio-897546

ABSTRACT

Abstract:The assessment of the preclinical neutralizing ability of antivenoms in Latin America is necessary to determine their scope of efficacy. This study was aimed at analyzing the neutralizing efficacy of a polyspecific bothropic-crotalic antivenom manufactured by BIRMEX in Mexico against lethal, hemorrhagic, defibrinogenating and in vitro coagulant activities of the venoms of Bothrops jararaca (Brazil), B. atrox (Perú and Colombia), B. diporus (Argentina), B. mattogrossensis (Bolivia), and B. asper (Costa Rica). Standard laboratory tests to determine these activities were used. In agreement with previous studies with bothropic antivenoms in Latin America, a pattern of cross-neutralization of heterologous venoms was observed. However, the antivenom had low neutralizing potency against defibrinogenating effect of the venoms of B. atrox (Colombia) and B. asper (Costa Rica), and failed to neutralize the in vitro coagulant activity of the venom of B. asper (Costa Rica) at the highest antivenom/venom ratio tested. It is concluded that, with the exception of coagulant and defibrinogenating activities of B. asper (Costa Rica) venom, this antivenom neutralizes toxic effects of various Bothrops sp venoms. Future studies are necessary to assess the efficacy of this antivenom against other viperid venoms. Rev. Biol. Trop. 65 (1): 345-350. Epub 2017 March 01.


ResumenEs necesario estudiar a nivel preclínico la capacidad neutralizante de los antivenenos producidos en América Latina, para conocer su espectro de cobertura. En este estudio se analizó la eficacia preclínica de un antiveneno poliespecífico botrópico-crotálico producido por BIRMEX, en México, para neutralizar los efectos letal, hemorrágico, desfibrinogenante y coagulante in vitro de los venenos de Bothrops jararaca (Brasil), B. atrox (Perú y Colombia), B. diporus (Argentina), B. mattogrossensis (Bolivia) y B. asper (Costa Rica). Se emplearon metodologías de laboratorio estándar en los análisis. En consonancia con estudios anteriores con diversos antivenenos botrópicos en América Latina, se observó un amplio patrón de neutralización de estos venenos heterólogos en la mayoría de los efectos estudiados. Sin embargo, el antiveneno mostró una baja capacidad neutralizante contra el efecto desfibrinogenante de los venenos de B. atrox (Colombia) y B. asper (Costa Rica) y no neutralizó la actividad coagulante in vitro del veneno de B. asper (Costa Rica) a la máxima razón antiveneno/ veneno empleada.


Subject(s)
Animals , Antivenins/pharmacology , Bothrops , Crotalid Venoms/toxicity , Immunologic Factors/pharmacology , Snake Bites/drug therapy , Neutralization Tests , Antivenins/immunology , Reproducibility of Results , Crotalid Venoms/immunology , Drug Evaluation, Preclinical , Immunologic Factors/immunology , Mexico
11.
Article in English | WPRIM | ID: wpr-184074

ABSTRACT

PURPOSE: Rabies is one of the most fatal diseases, but it is 100% preventable in animals by vaccination. In this study, we present the epidemiological features of, and national preventive measures against, rabies in Korea. MATERIALS AND METHODS: Data related to rabies and the population density of raccoon dogs in Korea were collected from the Animal and Plant Quarantine Agency, the Korean Centers for Disease Control and Prevention, and the National Institute of Environmental Research. Rabies diagnosis was confirmed with a fluorescent antibody test using brain samples of animals in accordance with the procedures described by the World Organization for Animal Health. Serological assays for dogs and cattle were conducted using the fluorescent antibody virus neutralization test. RESULTS: From 1993 to 2016, a total of seven human rabies cases and 437 animal rabies cases in five different species were reported. An increase in the distribution of bait vaccine seemed to be related to a dramatic decrease in rabies prevalence in endemic rabies regions. Two Korean provinces and the capital city, Seoul, were involved in rabies outbreaks. Korean rabies strains are most closely related to the eastern Chinese strain belonging to the Arctic-like lineage. The yearly seropositive rates ranged from 50.4% to 81.2% in dogs and from 25% to 60.5% in cattle residing in endemic rabies regions. CONCLUSION: This study indicates that national preventive measures, including mass vaccination and distribution of bait vaccines, have contributed to a substantial decrease in the number of rabies cases in Korea.


Subject(s)
Animals , Asian Continental Ancestry Group , Brain , Cattle , Diagnosis , Disease Eradication , Disease Outbreaks , Dogs , Epidemiology , Humans , Korea , Mass Vaccination , Neutralization Tests , Plants , Population Density , Prevalence , Quarantine , Rabies , Raccoon Dogs , Seoul , Vaccination , Vaccines
12.
Article in English | WPRIM | ID: wpr-184072

ABSTRACT

PURPOSE: The current live attenuated rabies vaccine must be replaced with a safer vaccine based on the ERAGS strain to prevent rabies in South Korea. We evaluated the safety and immunogenicity of a new strain in dogs and cattle. MATERIALS AND METHODS: The ERAGS strain, featuring two mutations altering two amino acids in a glycoprotein of rabies virus, was propagated in NG108-15 cells. We lyophilized the virus in the presence of two different stabilizers to evaluate the utilities of such preparations as novel rabies vaccines for animals. To explore safety and immunogenicity, dogs and cattle were inoculated with the vaccine at various doses via different routes and observed daily for 8 weeks post-inoculation (WPI). Immunogenicity was evaluated using a fluorescent antibody virus neutralization test or enzyme-linked immunosorbent assay. RESULTS: The two different stabilizers did not differ greatly in terms of maintenance of virus viability in accelerated stability testing. No clinical signs of rabies developed in dogs or cattle inoculated with the vaccines (10(7.0) FAID₅₀/mL). Dogs and cattle inoculated intramuscularly with 10(5.0) FAID₅₀/mL exhibited virus neutralization assay titers of 4.6 IU/mL and 1.5 to 0.87 IU/mL at 4 WPI, respectively. All control animals remained rabies virus–seronegative throughout, confirming that no contact transmission occurred between vaccinated and control animals. CONCLUSION: Our findings indicate that the new rabies vaccine is safe and immunogenic in dogs and cattle.


Subject(s)
Amino Acids , Animals , Cattle , Dogs , Enzyme-Linked Immunosorbent Assay , Glycoproteins , Korea , Microbial Viability , Neutralization Tests , Rabies Vaccines , Rabies virus , Rabies , Vaccines
13.
Article in English | WPRIM | ID: wpr-224461

ABSTRACT

Severe fever with thrombocytopenia syndrome (SFTS) is caused by the SFTS virus (SFTSV). The SFTSV appears to have a wide host range, as SFTSV-positive ticks have been isolated from both farm animals and wild rodents. Therefore, it is important to monitor SFTSV-positive animals to prevent the transmission of SFTSV from animals to humans. Previously, we developed a competitive enzyme-linked immunosorbent assay (cELISA) to detect SFTSV-specific antibodies from field animals and compared the cELISA results to those from an indirect immunofluorescence assay (IFA). In this study, cELISA results were compared to and evaluated against the results from both an IFA and a virus neutralization (VN) test of 193 bovine serum samples (including two bovine positive control sera) and 70 horse serum samples. The consistency (98.9%) between cELISA and VN results was higher than that (97.4%) between cELISA and IFA for the bovine serum samples. Similarly, for the horse serum samples, the consistency (88.6%) between cELISA and VN results was higher than that (84.3%) between the cELISA and IFA. These findings indicate that our newly developed cELISA can be used for surveillance or epidemiological studies of SFTSV in animals.


Subject(s)
Animals , Animals, Domestic , Antibodies , Enzyme-Linked Immunosorbent Assay , Epidemiologic Studies , Fever , Fluorescent Antibody Technique, Indirect , Horses , Host Specificity , Humans , Neutralization Tests , Rodentia , Thrombocytopenia , Ticks
14.
Article in English | WPRIM | ID: wpr-115776

ABSTRACT

Foot-and-mouth disease is one of the most important viral diseases of cloven-hoofed animals. Mass vaccination is an effective method to control the disease and is frequently utilized in endemic regions. Sufficient protection of young animals is important in mass vaccination campaigns. Maternal antibodies negatively affect the success of vaccination. Hence, determination of the optimal vaccination age is crucial for the uninterrupted protection of young animals. This study was performed to identify the effect of vaccine potency and booster administration on serum neutralizing antibody titers of calves with different levels of maternal antibodies. Calves (n = 111) on a state farm were used in this study. Oil adjuvant foot-and-mouth disease vaccines with 3 PD₅₀ and 6 PD₅₀ potencies were used with or without booster administration. Serum samples were collected each month up to day 120 postvaccination. Virus neutralization tests were used to measure the serum neutralizing antibody titers and estimate the protection period by using pre-determined cut-off values for protection. The results revealed that a vaccination with a 6 PD₅₀ potency vaccine, preferably followed by a booster dose, should be used to overcome maternal immunity for incessant protection.


Subject(s)
Agriculture , Animals , Antibodies , Antibodies, Neutralizing , Antibody Formation , Foot-and-Mouth Disease , Mass Vaccination , Methods , Neutralization Tests , Vaccination , Vaccine Potency , Vaccines , Virus Diseases
15.
Article in English | WPRIM | ID: wpr-115771

ABSTRACT

Swine vesicular disease (SVD) is a highly contagious viral disease that causes vesicular disease in pigs. The importance of the disease is due to its indistinguishable clinical signs from those of foot-and-mouth disease, which prevents international trade of swine and related products. SVD-specific antibody detection via an enzyme-linked immunosorbent assay (ELISA) is the most versatile and commonly used method for SVD surveillance and export certification. Inactivated SVD virus is the commonly used antigen in SVD-related ELISA. A recombinant SVD virus-like particle (VLP) was generated by using a Bac-to-Bac baculovirus expression system. Results of SVD-VLP analyses from electron microscopy, western blotting, immunofluorescent assay, and mass spectrometry showed that the recombinant SVD-VLP morphologically resemble authentic SVD viruses. The SVD-VLP was evaluated as a replacement for inactivated whole SVD virus in competitive and isotype-specific ELISAs for the detection of antibodies against SVD virus. The recombinant SVD-VLP assay produced results similar to those from inactivated whole virus antigen ELISA. The VLP-based ELISA results were comparable to those from the virus neutralization test for antibody detection in pigs experimentally inoculated with SVD virus. Use of the recombinant SVD-VLP is a safe and valuable alternative to using SVD virus antigen in diagnostic assays.


Subject(s)
Animals , Antibodies , Baculoviridae , Blotting, Western , Certification , Enterovirus B, Human , Enzyme-Linked Immunosorbent Assay , Foot-and-Mouth Disease , Mass Spectrometry , Methods , Microscopy, Electron , Neutralization Tests , Serologic Tests , Swine Vesicular Disease , Swine , Virus Diseases
16.
Article in English | WPRIM | ID: wpr-91210

ABSTRACT

Japanese encephalitis (JE) is an important zoonosis caused by the mosquito-transmitted JE virus (JEV), which is a causative agent of reproductive failure in pregnant sows. Detection of JEV antibodies in swine is performed by hemagglutination inhibition (HI), virus neutralization (VN), and the plaque reduction neutralization test (PRNT). The most stringent PRNT is the 90% endpoint PRNT (PRNT₉₀). These conventional assays are difficult to carry out in diagnostic laboratories with insufficient instruments or cell culture systems. An alternative assay that is easily conducted and time efficient is required. In this study, we improved the indirect enzyme-linked immunosorbent assay (I-ELISA) with clarified antigen for the detection of JEV antibodies. The I-ELISA results obtained from 175 swine serum samples were compared with HI, VN, and PRNT₉₀ results. The sensitivity of I-ELISA was 91.8%, 95.0%, and 94.7% compared with HI, VN, and PRNT₉₀ results, respectively. The specificity of I-ELISA was 92.2%, 94.7%, and 94.7% compared with HI, VN, and PRNT₉₀ results, respectively. Moreover, the I-ELISA results were significantly correlated with the HI (r = 0.93), VN (r = 0.95), and PRNT₉₀ (r = 0.92) results. These results suggest that the improved I-ELISA is useful for serosurveillance of JEV in swine.


Subject(s)
Antibodies , Asian Continental Ancestry Group , Cell Culture Techniques , Encephalitis Virus, Japanese , Encephalitis, Japanese , Enzyme-Linked Immunosorbent Assay , Hemagglutination , Humans , Neutralization Tests , Sensitivity and Specificity , Swine
17.
Braz. j. infect. dis ; 20(6): 546-555, Nov.-Dec. 2016. tab, graf
Article in English | LILACS | ID: biblio-828157

ABSTRACT

ABSTRACT Plesiomonas shigelloides isolated from water in Brazil was previously described as a hemorrhagic heat-labile cytotoxic-enterotoxin producer. We purified this toxin from culture supernatants using ion metallic affinity chromatography (IMAC) followed by molecular exclusion chromatography. The pure toxin presented molecular mass of 50 kDa and isoelectric point (pI) around 6.9 by 2D electrophoresis. When injected intravenously, the purified cytotoxic-enterotoxin induced also severe spasms followed by sudden death of mice. Hence, we entitled it as lethal cytotoxic-enterotoxin (LCE). The presence of membrane vesicles (MVs) on cell surfaces of P. shigelloides was observed by scan electron microscopy (SEM). From these MVs the LCE toxin was extracted and confirmed by biological and serological assays. These data suggest that P. shigelloides also exports this cytotoxic-enterotoxin by membrane vesicles, a different mechanism of delivering extra cellular virulence factors, so far not described in this bacterium.


Subject(s)
Animals , Male , Rats , Cell Survival/drug effects , Plesiomonas/metabolism , Cytoplasmic Vesicles , Virulence Factors , Rivers/microbiology , Enterotoxins/pharmacology , Vero Cells , Neutralization Tests , Microscopy, Electron, Scanning , Chlorocebus aethiops , Plesiomonas/pathogenicity , Plesiomonas/ultrastructure , Lethal Dose 50
18.
Arq. bras. med. vet. zootec ; 68(6): 1523-1530, nov.-dez. 2016. tab, graf, mapas, ilus
Article in Portuguese | LILACS, VETINDEX, LILACS, VETINDEX | ID: biblio-827933

ABSTRACT

A enfermidade ectima contagioso está difundida em todo o estado de São Paulo. Foram amostrados 42 (8,64%) cuidadores de animais e 444 (91,36%) ovinos (n=486). A prevalência de reagentes para vírus-neutralização foi de 67% (IC95%=62-71%) nos ovinos, e em seus cuidadores de 76% (IC95%=63-89%), sendo P=0,22, ou seja, não houve diferença estatística significativa entre as espécies. A distribuição dos títulos teve diferença estatística significativa entre as espécies, com P=0,0048. As variações de titulação foram de 0,6 a 2,1 tanto nos ovinos quanto nos seus cuidadores. Dentre os 42 cuidadores de ovinos participantes do estudo, 32 apresentaram títulos de anticorpos expressos por log10 acima de 0,6.(AU)


These diseases are all widespread in the State of São Paulo. 42 (8.64%) animal caregivers and 444 (91.36%) sheep (n=486) were sampled. The reagents Prevalence paragraph virus neutralization was 67% (95% CI = 62-71%) in sheep and 76% (95% CI = 63-89%) for caregivers, with P=0.22 not being a statistically significant difference between the species. One of the distribution titles had significant difference between statistics as species with P=0.0048. The titration variations were 0.6 to 2.1, both in sheep and their caregivers. Among the 42 sheep caregivers participating in the study, 32 had antibody securities denominated in log10 above 0.6.(AU)


Subject(s)
Humans , Animals , Ecthyma, Contagious/epidemiology , Ecthyma, Contagious/transmission , Rural Workers , Sheep/virology , Neutralization Tests/veterinary
19.
Article in English | WPRIM | ID: wpr-277965

ABSTRACT

Objective To develop neutralizing monoclonal antibodies (MAbs) against H10N8 avian influenza virus hemagglutinin and to identify the binding sites. Methods MAbs against hemagglutinin of H10N8 avian influenza virus were developed by genetic engineering. Neutralizing MAbs were screened by microneutralization assay,and then tested by enzyme-linked immunosorbent assay and Western blot to identity the binding sites.The homology modeling process was performed using Discovery Studio 3.5 software,while the binding epitopes were analyzed by BioEdit software. Results One MAb that could neutralize the H10N8 pseudovirus was obtained and characterized. Analysis about epitopes suggested that the antibody could bind to the HA1 region of hemagglutinin,while the epitopes on antigen were conserved in H10 subtypes.Conclusions One neutralizing antibody was obtained by this research.The MAb may potentially be further developed as a pre-clinical candidate to treat avian influenza H10N8 virus infection.


Subject(s)
Antibodies, Monoclonal , Allergy and Immunology , Antibodies, Neutralizing , Allergy and Immunology , Antibodies, Viral , Allergy and Immunology , Enzyme-Linked Immunosorbent Assay , Epitopes , Allergy and Immunology , Hemagglutinin Glycoproteins, Influenza Virus , Allergy and Immunology , Influenza A Virus, H10N8 Subtype , Neutralization Tests
20.
Article in English | WPRIM | ID: wpr-24787

ABSTRACT

In this study, the seroprevalences of measles, mumps, and rubella antibodies in infants were determined to assess the immunization strategy and control measures for these infectious diseases. Serum samples from infants < 1 year of age and their mothers were collected to measure the concentrations of specific IgG antibodies to measles, mumps, and rubella by enzyme-linked immunosorbent assay. For selected infant serum samples, measles-specific neutralizing antibody levels were determined by using the plaque reduction neutralization test. The sera from 295 of infants and 80 of their mothers were analyzed. No infants had past measles, mumps, or rubella infections. Almost all infants < 2 months of age were positive for measles and rubella IgG antibodies. However, seroprevalence of measles and rubella antibodies decreased with age, and measles IgG and rubella IgG were barely detectable after 4 months of age. The seroprevalence of mumps antibodies was lower than that of measles and rubella antibodies in infants ≤ 4 months old, and mumps IgG was barely detectable after 2 months of age. The seropositivity of measles-specific neutralizing antibody was 63.6% in infants aged 2 months and undetectable in infants ≥ 6 months old. Because the seropositivity rates of measles, mumps, and rubella antibodies were low after the first few months of age in Korean infants, active immunization with vaccines is strongly recommended for infants aged 6–11 months when measles is epidemic. Timely administration of the first dose of measles-mumps-rubella vaccine at 12 months of age should be encouraged in non-epidemic situations.


Subject(s)
Antibodies , Antibodies, Neutralizing , Communicable Diseases , Enzyme-Linked Immunosorbent Assay , Humans , Immunization , Immunoglobulin G , Infant , Korea , Measles , Measles-Mumps-Rubella Vaccine , Mothers , Mumps , Neutralization Tests , Rubella , Seroepidemiologic Studies , Vaccination , Vaccines
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