2019–2020 measles in the Republic of Guinea: epidemic features and herd immunity

Introduction. In connection with the Ebola epidemic in the West African countries, including the Republic of Guinea, a failure in implementing measles immunization program was noted. A proportion of measles seronegative subjects in 2017 was 52.4% of total examined individuals. In 2018, a high proportion of measles cases among children aged 1–5 years (61.6%) was identified. In order to stop the 2018 outbreak, the Supplemental Immunization Campaign was conducted in the Konakri and Nzerekore prefectures in the Republic of Guinea. The aim of this study was to examine the 2019–2020 measles epidemic situation and assess the measles population immunity in the Republic of Guinea. Materials and methods. Measles-specific antibodies were examined in 1697 blood serum samples collected from residents of different regions of the Republic of Guinea, aged from 7 months to 76 years, obtained in 2019–2020, and tested retrospectively. The ELISA test systems Anti-Measles Virus ELISA (IgM) Euroimmun and Anti-Measles Virus ELISA (IgG) Euroimmun (Germany) were used. The presence of serum IgM measles antibodies was considered as acute measles infection. Statistical analysis was performed using the software package Statistica 6.0. Results. Blood sera (n = 638) were tested for IgM-measles, and in 46.6% of cases the diagnosis was confirmed by laboratory tests. The biggest proportion of the total cases (61.6%) was found in children aged 1–4 years. The second most important age group was 5–9 years of age, the third is children under 1 year: 18.5% and 11.8% of the total number of patients, respectively. Measles infection was registered in vaccinated patients in 7.4% of the total number of laboratory-confirmed cases. 1059 subjects were examined for IgG measles antibody. The lowest seroprevalence rate was found among children under 4 years of age (47.8%). The highest (85.5%) was found among subjects of 40 years old and older. Conclusion. Measles in GR remains a poorly controlled infection. As in the previous years of observation (2017–2018), children under 5 years of age are the most vulnerable cohort of the population, despite the 2018 DI campaign conducted in a number of GR territories. More problems with the measles control in the Republic of Guinea are expected in the period from 2021, as along with the COVID-19 epidemic, Ebola is repeatedly registered in the country. The Republic of Guinea particularly requires assistance from the international community to implement the WHO measles elimination program on a global scale.

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Detection of measles cases in the Republic of Guinea in 2017–2018

Russian Journal of Infection and Immunity ◽

10.15789/2220-7619-dom-1333 ◽

2020 ◽

Vol 10 (3) ◽

pp. 570-574

Author(s):

I. N. Lavrentieva ◽

M. A. Bichurina ◽

A. Y. Antipova ◽

J. Camara ◽

N.F. Magassouba

Keyword(s):

Antibody Level ◽

Measles Virus ◽

Age Groups ◽

Cold Chain ◽

Epidemiological Surveillance ◽

Serum Samples ◽

Igg Antibody ◽

Republic Of Guinea ◽

Measles Vaccination ◽

The Republic

In 2017, WHO reported 596 confirmed measles cases in Guinea Republic connected to the 2016–2017 epidemic outbreak that was stopped after additional immunization (SIA) against measles in two provinces of the country. Improving the effectiveness of SIA is associated with the identification of epidemiologically significant groups of the population. The aim of the study was to analyze 2017–2018 measles cases and assess population immunity to measles virus in the Republic of Guinea. Materials and methods. A total of 810 blood serum samples collected from patients with maculo-papular rash and clinical diagnosis “measles?” were tested for measles virus-specific IgM-and IgG antibody level. 445 sera of conditionally healthy individuals aged 7 months to 67 years were examined for anti-measles virus IgG antibody level. Immunoglobulins of classes M and G were detected by ELISA with test systems «Anti-Measles Virus ELISA (IgM)» (Euro immun, Germany) and «Anti-Measles Virus ELISA (IgG)» (Euroimmun, Germany). Results and discussion.In 2017–2018, the epidemic process of the measles in the Republic of Guinea proceeded very intensively, being markedly prevalent in children among age groups. In 2018, more than half of the cases (61.6%) were identified in children aged 1 to 5 years old; the second most abundant age group was children under one year (18.6%), probably due to violated measles vaccination, which in GR are subject to children of nine months of age. It was found that 16.4% of patients (60 out of 366) had documented data on measles vaccination. Potentially, high proportion of measles cases among pre-vaccinated subjects was due to insufficient immune response to a single immunization in children of 9 months of age. Moreover, lowered vaccine-related properties might also be violated “cold chain” during vaccine transportation occurring in tropical climate. Analyzing 445 subjects revealed that total number of measles virus seronegative subjects was 8.3%. However, the vast majority of them were children and young adults aged 7 months to 22 years, where 52.4% of seronegative subjects were identified. Thus, the data obtained indicate that intensive measles virus circulation in human population was continued that necessitate interventions for improving epidemiological surveillance, extend routine measles vaccination coverage and conduct SIAs against measles in GR.

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The Status of Humoral Immunity to Parvovirus B19 in Population of Certain Geographical Regions

Journal of microbiology epidemiology immunobiology ◽

10.36233/0372-9311-2020-97-3-5 ◽

2020 ◽

Vol 97 (3) ◽

pp. 233-241

Author(s):

Irina N. Lavrentieva ◽

Irina V. Khamitova ◽

Jacob Camara ◽

Anastasia Yu. Antipova ◽

Maina A. Bichurina ◽

...

Keyword(s):

Central Asia ◽

Humoral Immunity ◽

Migrant Workers ◽

Parvovirus B19 ◽

Age Groups ◽

Seroprevalence Rate ◽

Serum Samples ◽

Republic Of Guinea ◽

Geographical Regions ◽

The Republic

Introduction. In a number of countries, including Russia, there is no systematic registration and reporting of parvovirus infection cases; the extent of its spread can be estimated by using humoral immunity rates.Purpose of the study: Assessment of seroprevalence of parvovirus B19 (B19V) in different age groups of population of Russia, Central Asia, and West Africa.Materials and methods. A total of 1,732 blood serum samples from residents of St. Petersburg and Nur-Sultan, migrant workers from Uzbekistan and Tajikistan, residents of the Republic of Guinea were studied for IgG antibodies to B19V.Results. The highest seroprevalence rates were identified in St. Petersburg and Nur-Sultan (62–65%); the lowest rates were registered among migrant workers from Uzbekistan and Tajikistan (47%). The results for the Republic of Guinea showed a B19V seroprevalence rate of 53%. It was found that there is an increasing trend of seropositivity with age; the percentage of seropositive individuals clearly increases in older age groups: up to 55% — among migrant workers from Central Asia and residents of the Republic of Guinea; up to 80–85% — among residents of St. Petersburg and Nur-Sultan.Discussion. The obtained results confirm the worldwide occurrence of parvovirus infection. People susceptible to infection can cause infection spreading in high-risk groups — among pregnant women, immunodeficient patients, blood product recipients, and cancer patients.

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Rise in 2017-2018 measles morbidity in Serbia and Northwest Russia

Russian Journal of Infection and Immunity ◽

10.15789/2220-7619-rim-1342 ◽

2020 ◽

Vol 10 (4) ◽

pp. 729-734

Author(s):

V. D. Stoiljkovic ◽

M. A. Bichurina ◽

I. N. Lavrentieva ◽

S. B. Filipovic-Vignjevic ◽

M. D. Bancevic ◽

...

Keyword(s):

Incidence Rate ◽

Measles Virus ◽

Federal District ◽

Test System ◽

Vaccination Status ◽

Serum Samples ◽

Virus Genotypes ◽

The Russian Federation ◽

The Republic ◽

Measles Incidence

In 2017, the WHO registered 23,927 measles cases in 44 out of 53 countries in the European region. In 2018, measles incidence rate increased up to 82,599 cases registered in 48 countries of the region, with a large number of measles-associated deaths. Overall, 72 measles fatalities were registered in 10 European countries, including Serbia (15 cases).Aim of the study: to characterize 2017—2018 epidemiological upsurge of measles incidence rate observed in the Republic of Serbia (RS) and the Northwestern Federal District (NWFD) of the Russian Federation.Materials and methods. During the 2017—2018 season, 944 serum samples were collected from patients with measles, rubella, or exanthematous diseases in the NWFD and tested in the Laboratory of Virology at the St. Petersburg Regional Centre for Measles Surveillance (SPbRC). In 2017—2018, 2,946 serum samples from the Republic of Serbia were analyzed in the SPbRC by using ELISA with IgM measles test system (Vector-Best, Russia; or Siemens, Germany). Urine and swab samples were examined by RT-PCR and used for isolation and genotyping of measles viruses.Results. From 2017 to 2018, 5,798 measles cases were registered in the RS, among which 2,946 were laboratory-confirmed (serological testing and/or PCR). Unvaccinated subjects or those with unknown vaccination status accounted for majority of the cases. Children under 5 years of age and adults aged 30 years and over dominated among measles patients. During this season, 15 deaths were reported. Several genotypes of measles virus circulated in the RS, e.g. В3 Dublin, D8 Gir Somnath, and D8 Herborn. In 2018, 109 measles cases were recorded in the NWFD, 5 of which were imported from abroad. Among patients, adults comprised 64.2%, wherein 74.3% were covered by unvaccinated subjects or those with unknown vaccination status. Rise in measles incidence rate linked to multiple importations of various measles virus genotypes: В3 Kabul; B3 Dublin; D8 Frankfurt; D8 Cambridge; and D8 Gir Somnath.

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A herd immunity to measles and rubella viruses in the population of the Republic of Serbia

Russian Journal of Infection and Immunity ◽

10.15789/2220-7619-ahi-1496 ◽

2021 ◽

Vol 11 (1) ◽

pp. 171-176

Author(s):

M. A. Bichurina ◽

S. Filipovic-Vignjevic ◽

A. Yu. Antipova ◽

M. Bancevic ◽

I. N. Lavrentieva

Keyword(s):

Measles Virus ◽

Herd Immunity ◽

Age Groups ◽

Age Group ◽

Igg Antibodies ◽

Mmr Vaccine ◽

Igg Antibody ◽

Group I ◽

Study Results ◽

The Republic

According to the WHO Strategic Plan, measles should be eradicated in 2020 in the five WHO Regions including European Region. However, large measles outbreaks are being periodically registered in diverse European countries. In the Republic of Serbia (SRB), 5,076 measles cases were detected in 2018, among which 15 cases were fatal.Aim of the study was to examine herd immunity to measles and rubella viruses in the population of the Republic of Serbia.Materials and methods. Blood serum samples obtained in 2018 and 2019 from conditionally healthy residents of the Republic of Serbia were tested for the presence of IgG antibodies to measles and rubella viruses in five age groups: I — children from 2 to 6 years old, II — children from 8 to 14 years old, III — 15 to 24 years old, IV — 25 to 49 years old and V — over 50 years old. A total of 1000 samples were obtained, 200 sera in each group. Enzygnost® Anti-Measles virus/IgG and Enzygnost® Anti-Rubella virus/IgG ELISA test systems (Siemens Healthcare Diagnostics Products GmbH, Germany) were used according to the manufacturer's instructions.Results. Overall, around 23.0% and 33.7% of the surveyed persons had no or low level of anti-measles IgG antibody (≥ 275.0 — ≤ 1000.0 IU/1). In age group I, 60% children contained no or “low” anti-measles antibodies titer (29.5% and 30.5%, respectively). In addition, low antibody titer level was mainly detected in individuals from age group II and III (p < 0.05). A third of children under 8—14 contained high IgG-antibodies titer against measles (> 3000.0 IU/l) that might serve as an evidence that such subjects recently recovered after measles. Similar results were obtained for IgG antibodies to rubella in the same age groups.Discussion. The study results evidence about altered routine immunization against measles and rubella in children aged 12—15 months (first vaccination) and those at age of 6—7 years (revaccination) with MMR vaccine. The data obtained correlate with official data on coverage with measles and rubella vaccines in the Republic of Serbia.

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A survey of examining herd measles immunity in adults over 35 years old

Russian Journal of Infection and Immunity ◽

10.15789/2220-7619-aso-1302 ◽

2020 ◽

Vol 10 (2) ◽

pp. 381-386 ◽

Cited By ~ 1

Author(s):

L. V. Rubis

Keyword(s):

Measles Virus ◽

High Titer ◽

Herd Immunity ◽

Age Groups ◽

High Risk Group ◽

Protective Level ◽

Protective Antibody ◽

The Republic ◽

High Level ◽

Post Infectious

A high measles incidence rate has been registered in Russia in recent years, with adults being actively involved in the epidemic process (about 40% of patients), thereby underlying relevance of assessing herd immunity in different age groups to measure its risk. The data on examining serum antibodies to measles virus in 402 residents of Petrozavodsk are shown: 164 and 238 subjects were born in 1948–1968 (51–71 years) and 1970–1983 (36–50 years), respectively. It was found that the second group had significantly higher percentage not only of seropositive persons (94.1±1.5 vs. 77.4±3.3%, respectively), but also frequency of detected high IgG level (5 and more IU/l) reaching 39.7±3.5 vs. 15.4±5.8%, respectively. Analysis of vaccination history showed that of 351 people with protective antibody levels, 20.9% were vaccinated once or twice, 14 of them in childhood and 63 within the 15 years prior to the study. Of the 51 people with no measles antibodies or below protective level, 13.7% were vaccinated: five in childhood, and two within the last 15 years. Among those who was born in 1948–1968, 87.1±2.2% provided no information about previous vaccinations and probably were not vaccinated. In this group, percentage of those examined with a protective antibody level was significantly higher than in the 36–50 years group — 87.1±2.2 and 62.2±4.3%, respectively. In addition, 23 subjects confirmed that they recovered after measles in childhood. Of these, antibodies were detected in 21 subjects, including 9 having serum titer at level of 5 or more IU/ml. Until 1969, the Republic of Karelia registered a high level of measles morbidity (477–2176,0 per 100 thousand). The predominance in the group born before 1969, individuals seropositive to measles mainly at high titer, indicates that intense post-infectious immunity was preserved. The lack of protective level of antibodies to measles virus in 22.6% of persons aged 36–50 years (1969–1983 year of birth), due to the low level of post-infectious and insufficient durability of post-vaccination immunity allowing to definer them as a high risk group for measles infection.

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Study of the prevalence of antibodies to some arboviruses in the population of the Republic of Guinea

Voprosy Virusologii ◽

10.36233/0507-4088-74 ◽

2021 ◽

Vol 66 (5) ◽

pp. 346-353

Author(s):

E. V. Naidenova ◽

M. Yu. Kartashov ◽

K. S. Zakharov ◽

A. P. Shevtsova ◽

M. G. Diallo ◽

...

Keyword(s):

Clinical Signs ◽

Hemorrhagic Fever ◽

Serum Samples ◽

African Region ◽

Republic Of Guinea ◽

Disease Patterns ◽

Urgent Task ◽

The Republic ◽

Total Structure ◽

Batai Virus

Introduction. Acute febrile diseases kill more than 250,000 people annually in West Africa. Malaria and typhoid fever traditionally occupy most of the total structure of registered fevers. However, these data do not fully reflect the true overall disease patterns in the West African region. This is due to the fact that diagnosis is mainly based on the clinical signs of the infectious process, suggesting that a certain number of diseases may be caused by arboviruses. The detection of specific antibodies (ABs) to infectious pathogens in the blood sera of residents of a particular area is a reliable indicator of the circulation of these pathogens in a particular territory.The aim of this study was to determine the prevalence of antibodies to a number of arboviruses: Dengue (DENV), West Nile (WNV) (family Flaviviridae), Crimean-Congo hemorrhagic fever (orthonairo)virus (CCHFV), Batai (Batai virus), Bhanja (BHAV) (order Bunyavirales), Chikungunya (CHIKV), and Sindbis (SINV) (family Togaviridae) in the population of the Republic of Guinea.Material and methods. In total, a panel of 2,620 blood serum samples from people living in all landscape and geographical areas of Guinea was collected for the study. Detection of IgG antibodies was performed using an enzyme-linked immunoassay (ELISA).Results. In total, ABs to Batai virus were detected in 144 samples (5.5%), BHAV in 58 (2.2%), WNV in 892 (34.0 %), DENV in 659 (25.2 %), CCHFV in 58 (2.2 %), CHIKV in 339 (12.9 %), and SINV in 52 samples (2.0 %).Discussion. The obtained results indicate serological evidence of the spectrum of arboviruses in the population of all landscape and geographical zones of the Republic of Guinea, confirming their active circulation in this territory.Conclusion. Given the high epidemiological significance of arbovirus infectious diseases, it is an urgent task to continue studying its share in the structure of febrile diseases in the territory of the Republic of Guinea.

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Prevalence of hepatitis E virus in thalassemia patients with hepatitis C in Tehran, Iran

Iranian Journal of Microbiology ◽

10.18502/ijm.v11i6.2226 ◽

2020 ◽

Author(s):

Najmeh Dalvand ◽

Azadeh Dalvand ◽

Zohreh Sharifi ◽

Seyed Masoud Hosseini

Keyword(s):

Risk Groups ◽

Hepatitis E ◽

Oral Route ◽

Elisa Test ◽

Seroprevalence Rate ◽

Rt Pcr ◽

Serum Samples ◽

Thalassemia Patient ◽

Significant Difference ◽

Tehran Province

Background and Objectives: HEV infection is predominantly spread via the fecal-oral route; however, due to the presence of HEV RNA in the serum of healthy blood donors, there is a possibility of the transmissibility of HEV infection through blood. Multi-transfused thalassemia patients are one of the high risk groups for blood borne viruses. In this study, we evaluated the prevalence of HEV antibodies and HEV-RNA in thalassemia patients with HCV infection. Materials and Methods: 120 anti-HCV positive thalassemia patient serum samples from Tehran province during April-June 2019 were assessed for the presence of total anti-HEV antibodies using of HEV Ab ELISA kit. All serum samples were assayed by Nested RT-PCR to detect HEV-RNA. Results: The results of ELISA test showed that 2 out of 120 (1.67%) samples were positive for anti-HEV Ab. There was no statistically significant difference between anti-HEV antibody prevalence rate and sex, age and other risk factors. None of 120 (0.00%) samples were positive for HEV-RNA by Nested RT-PCR. Conclusion: Seroprevalence of HEV in our study group was 1.67% which is less than HEV seroprevalence rate in Iranian general population. Therefore, it can be conclude that transmission of HEV infection via blood transfusion seems to be uncommon in Iran and the fecal-oral route can be the predominant mode of transmission in Iran; however, more studies are required to confirm this issue.

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Seroprevalence of SARS-CoV-2 in the West Bank region of Palestine: a cross-sectional seroepidemiological study

BMJ Open ◽

10.1136/bmjopen-2020-044552 ◽

2021 ◽

Vol 11 (2) ◽

pp. e044552

Author(s):

Nouar Qutob ◽

Faisal Awartani ◽

Zaidoun Salah ◽

Mohammad Asia ◽

Imad Abu Khader ◽

...

Keyword(s):

West Bank ◽

Herd Immunity ◽

Secondary Outcome ◽

Seroprevalence Rate ◽

Serum Samples ◽

The West ◽

Serological Tests ◽

Cross Sectional ◽

Blood Samples ◽

Medical Laboratories

ObjectivesSeroprevalence rates are important indicators to the epidemiology of COVID-19 and the extent of the pandemic given the existence of asymptomatic cases. The purpose of this study is to assess the seroprevalence rate in the Palestinian population residing in the West Bank.SettingThe study involved 1355 participants from 11 governorates, including 112 localities in the West Bank and 1136 individuals visiting Palestinian medical laboratories.ParticipantsBlood samples were collected between 15th June 2020 and 30th June 2020 from 1355 individuals from randomly selected households in the West Bank, in addition to 1136 individuals visiting Palestinian medical laboratories between the 1st May 2020 and 9th July 2020 for a routine check-up.Primary and secondary outcome measuresOut of the 2491 blood samples collected, serological tests for 2455 adequate serum samples were done using an immunoassay for qualitative detection of antibodies against SARS-CoV-2. Seroprevalence was estimated as the proportion of individuals who had a positive result in the total SARS-CoV-2 antibodies in the immunoassay.ResultsThe random sample of Palestinians living in the West Bank yielded 0% seroprevalence with 95% and an adjusted CI (0% to 0.0043%), while the lab referral samples yielded an estimated seroprevalence of 0.354% with 95% and an adjusted CI (0.001325% to 0.011566%).ConclusionsOur results indicate that as of mid-June 2020, seroprevalence in Palestine persists low and is inadequate to provide herd immunity, emphasising the need to maintain health measures to keep the outbreak under control. Population-based seroprevalence studies are to be conducted periodically to monitor the SARS-CoV-2 seroprevalence in Palestine and inform policymakers about the efficacy of their surveillance system.

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Herd immunity to SARS-CoV-2 among the population of the Republic of Belarus amid the COVID-19 pandemic

Russian Journal of Infection and Immunity ◽

10.15789/2220-7619-hit-1798 ◽

2021 ◽

Vol 11 (5) ◽

pp. 887-904

Author(s):

A. Yu. Popova ◽

A. A. Tarasenko ◽

V. Yu. Smolensky ◽

S. A. Egorova ◽

V. S. Smirnov ◽

...

Keyword(s):

Herd Immunity ◽

Age Groups ◽

Statistical Processing ◽

Threshold Level ◽

Test System ◽

Elisa Test ◽

Surface Glycoprotein ◽

Pasteur Institute ◽

The Republic ◽

Questionnaire Method

Objective was to investigate the SARS-CoV-2 collective immunity status of the population of Belarus within the context of the COVID-19 pandemic. Materials and methods. The work was carried out according to the methodology for assessing SARS-CoV-2 population immunity, developed by Rospotrebnadzor Russia and the Ministry of Health of Belarus with the participation of the St. Petersburg Pasteur Institute, taking into account WHO recommendations. The Bioethics Committee of Belarus and the local ethics committee of the St. Petersburg Pasteur Institute approved the study. Selection of participants was carried out using a questionnaire method and online technology (internet, cloud server). Volunteers were randomized into seven age groups (years of age): 1–17; 18–29; 30–39; 40–49; 50–59; 60–69; and 70+. Regional randomization ensured proportional representation of volunteers from each region, and no more than 30 people were included from one enterprise. In accordance with manufacturer instructions, blood plasma samples were analyzed for: IgG antibodies (Abs) to the SARS-CoV-2 nucleocapsid (Nc) using a quantitative ELISA test system; and IgG Abs to the receptor binding domain (RBD) of the SARS-CoV-2 S (spike) surface glycoprotein using a qualitative ELISA test system. Statistical processing was carried out using Excel 2010 and other software. Statistical differences were designated as significant when p < 0.05, unless otherwise indicated. Results. The level of seroprevalence, in terms of Abs to Nc among the Belarusian population, was 38.4% (95% CI 37.6–45.4). The highest Ab levels were found among individuals in older age groups (50-70+ years old). The lowest were found in children 1–17 years old and in young people 18–39 years old The distribution of seroprevalence across Belarusian regions was relatively homogeneous, with the exception of the Minsk Region, where a statistically significant decrease in the indicator was noted. In terms of profession, the largest share of seropositive individuals was found among transportation workers; the smallest was found in business. The moderate COVID-19 incidence has not led to a dramatic increase in the number of contacts. The base reproduction number (R0) was 1.3. In the Republic of Belarus, there was a moderate level of asymptomatic COVID-19 among seropositive individuals (45.3% [95% CI 44.0–46.7]). This form of infection was observed most often among children aged 1–17 years old (65.0% [95% CI 61.3–68.6]). In parallel with seroprevalence assessment, SARS-CoV-2 vaccination was carried out. We used two vaccines: Gam-COVID-Vac (also known as Sputnik V, developed by Gamaleya National Center for Epidemiology and Microbiology, Russia); and BBIBP-CorV (Sinopharm, PRC). Vaccination against SARS-CoV-2 was accompanied by an increase in the level of anti-RBD Abs (95% [95% CI 94.7–96.7]). Taking into account the vaccination of a subset of the population with BBIBP-CorV, the overall herd immunity, inferred from the analyzed indicators (presence of anti-Nc or anti-RBD Abs), was 47.1% (95% CI 46.3–48.0). Conclusion. COVID-19 in Belarus was characterized by a moderately pronounced course of the epidemic process. The threshold level of herd immunity to SARS-CoV-2 has not yet been reached, as a result of which the conditions for progression of the epidemic remain.

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Контроль эффективности вакцинопрофилактики инфекционного бронхита кур в птицеводческих хозяйствах Республики Крым

Vestnik APK Verhnevolzh`ia ◽

10.35694/yarcx.2019.46.2.008 ◽

2019 ◽

pp. 37-43

Author(s):

S.I. Danilchenko ◽

M.A. Pasunkina ◽

I.B. Ionkina ◽

N.G. Kosharnyi

Keyword(s):

Blood Serum ◽

Elisa Test ◽

Serum Samples ◽

Humoral Immune ◽

Poultry Farms ◽

Different Ages ◽

The Crimea ◽

Antibody Titers ◽

The Republic ◽

Production Period

Целью исследований было проведение серологического мониторинга инфекционного бронхита кур (ИБК), анализ технологических схем вакцинаций и изучение напряжённости гуморального иммунитета к вирусу ИБК. Исследования проводились в Республике Крым в течение 20172018 гг. Материалом для исследований служили образцы сывороток крови от кур разного возраста (молодняк, взрослая птица), поступивших из двух ведущих птицеводческих предприятий Крыма. Определение антител к вирусу ИБК проводили методом иммуноферментного анализа (ИФА). Всего было исследовано 1324 образца сывороток крови от птицы разного возраста. Поствакцинальные антитела обнаружены в 1317 пробах (99,4). Установлено, что применение в обследуемых хозяйствах для профилактики ИБК живых и инактивированных одно и многовалентных вакцин отечественного и импортного производства в соответствии с действующим регламентом вакцинопрофилактики и разработанными в хозяйствах технологическими схемами вакцинации создаёт полноценную специфическую защиту у вакцинированного поголовья на протяжении всего периода продуктивности. Отмечено, что постепенное нарастание средних титров антител у птиц каждой следующей возрастной группы с пиком в 140 и 150дневном возрасте соотносится с классической схемой формирования гуморального иммунитета при применении живых и инактивированных вакцин. В дальнейшем у кур старше 300суточного возраста появляются достаточно пёстрые титры антител к ИБК, что может свидетельствовать о возможной циркуляции полевого вируса ИБК. В связи с этим имеется необходимость систематического мониторинга уровня антител к вирусу ИБК, что позволит и дальше контролировать эпизоотическую ситуацию к данному заболеванию в птицеводческих хозяйствах Крыма.The aim of the research was to conduct serological monitoring of avian infectious bronchitis (AIB), the analysis of technological schemes of vaccinations and the study of the intensity of humoral immune response to the AIB virus. The researches were carried out in the Republic of Crimea during 20172018. The material for the researches were samples of blood serum from chickens of different ages (young birds, mature birds) received from two leading poultry farms of the Crimea. Determination of antibodies to AIB virus was conducted by enzyme multipled immunoassay (ELISA test). A total of 1324 blood serum samples from birds of different ages were examined. Vaccineinduced antibodies were found in 1317 samples (99.4). It has been established that the use of live and inactivate monovalent and multivalent vaccines of domestic and foreign production in the surveyed farms for the prevention of AIB in accordance with the current vaccinal prevention schedule and the vaccination technological schemes developed on the farms creates full specific protection for the vaccinated livestock throughout the entire production period. It is noted that a gradual increase in the average antibody titers in birds of each subsequent age group with a peak at 140 and 150 days of age correlates with the classical scheme for the formation of antibody mediated immunity with the use of live and inactivate vaccines. Further chickens older than 300 days of age appear to have rather variegated antibody titers to AIB which may indicate a possible circulation of the field AIB virus. In this regard there is a need for systematic monitoring of the level of antibodies to the AIB virus which will allow further control of the epizootic situation to this disease in the poultry farms of the Crimea.

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