Age-dependent acquisition of IgG antibodies to Shigella serotypes-a retrospective analysis of seroprevalence in Kenyan children with implications for infant vaccination

Background

Shigellosis mainly affects children under 5 years of age living in low- and middle-income countries, who are the target population for vaccination. There are, however, limited data available to define the appropriate timing for vaccine administration in this age group. Information on antibody responses following natural infection, proxy for exposure, could help guide vaccination strategies.

Methods

We undertook a retrospective analysis of antibodies to five of the most prevalent Shigella serotypes among children aged <5 years in Kenya. Serum samples from a cross-sectional serosurvey in three Kenyan sites (Nairobi, Siaya, and Kilifi) were analyzed by standardized ELISA to measure IgG against Shigella sonnei and Shigella flexneri 1b, 2a, 3a, and 6. We identified factors associated with seropositivity to each Shigella serotype, including seropositivity to other Shigella serotypes.

Results

A total of 474 samples, one for each participant, were analyzed: Nairobi (n = 169), Siaya (n = 185), and Kilifi (n = 120). The median age of the participants was 13.4 months (IQR 7.0-35.6), and the male:female ratio was 1:1. Geometric mean concentrations (GMCs) for each serotype increased with age, mostly in the second year of life. The overall seroprevalence of IgG antibodies increased with age except for S. flexneri 6 which was high across all age subgroups. In the second year of life, there was a statistically significant increase of antibody GMCs against all five serotypes (p = 0.01-0.0001) and a significant increase of seroprevalence for S. flexneri 2a (p = 0.006), S. flexneri 3a (p = 0.006), and S. sonnei (p = 0.05) compared with the second part of the first year of life. Among all possible pairwise comparisons of antibody seropositivity, there was a significant association between S. flexneri 1b and 2a (OR = 6.75, 95% CI 3-14, p < 0.001) and between S. flexneri 1b and 3a (OR = 23.85, 95% CI 11-54, p < 0.001).

Conclusion

Children living in low- and middle-income settings such as Kenya are exposed to Shigella infection starting from the first year of life and acquire serotype-specific antibodies against multiple serotypes. The data from this study suggest that Shigella vaccination should be targeted to infants, ideally at 6 or at least 9 months of age, to ensure children are protected in the second year of life when exposure significantly increases.

Sero-prevalence and factors associated with anti-Brucella antibodies in slaughter livestock in Uganda

Introduction

Brucellosis is endemic in Uganda and is a major cause of production losses in livestock. Early detection and quantification of the disease is vital for its control and eradication. The aim of this study was to assess the sero-prevalence and factors associated with anti-Brucella antibodies in slaughtered livestock.

Materials and methods

Sera from 886 cattle, 925 small ruminants, and 900 pigs were collected from regional abattoirs in Northern, Eastern and Central Uganda. To estimate sero-prevalence, sera were serially tested using a combination of the Rose Bengal Test (RBT) and Native Hapten (NH) immunoprecipitation test. True sero-prevalence was estimated using the Rogan-Gladden estimator considering the sensitivity and specificity of the NH immunoprecipitation test. Multivariable logistic regression was used to assess factors associated with seropositivity for anti-Brucella antibodies.

Results and discussion

Small ruminants showed the highest seroprevalence (6.7%, 95% CI = 4.2-7.1) followed by cattle (3.8%, 95% CI = 2.4-4.9) and pigs (2.8%, 95% CI = 1.1-2.9). Seropositivity for anti-Brucella antibodies was associated with region of origin (OR = 4.6,95%CI=1.49-17.75, p = 0.013) for cattle; sex (OR = 2.90, 95% C = 1.5-6.34, p = 0.004), age (OR=4.04, 95% CI = 1.07-8.52, p = 0.006) and species (OR = 2.53, 95% CI = 1.08-6.98, p = 0.048) for small ruminants; and finally sex for pigs (OR = 2.88, 95% CI = 1.07-8.52, p = 0.041). Progressive control interventions must include both cattle and small ruminants since they play a bigger role in the maintenance and dissemination of Brucella. The interventions should adopt a risk-based approach with regions at higher risk being given top priority. Bacteriological and molecular studies should be undertaken to clarify the role of pigs and the goat-cattle cross infections in the epidemiological cycle of brucellosis in Uganda.

Farm characteristics and sero-prevalence of porcine reproductive and respiratory syndrome virus (PRRSV) antibodies in pigs of Nepal

BACKGROUND

Porcine reproductive and respiratory syndrome is a highly infectious disease of swine caused by PRRS virus (PRRSV).

OBJECTIVES

To evaluate the prevalence of PRRSV antibodies in the four districts of hilly and terai regions of Nepal. Toassess the farm characteristics through a questionnaire interview of farmersregarding management practices and PRRS.

METHODS

A cross-sectional study was conducted from July 2020 to June 2021 to determine the sero-prevalence of PRRSV in pigs. A total of 180 porcine serum samples were collected from 23 pig farms and tested for PRRSV antibodies by ELISA. Alongside, farm characteristics were also assessed through questionnaire to determine the level of biosecurity measures in the farm, knowledge of the disease and possible control mechanisms.

RESULTS

Out of 180 samples, 37 were tested positive resulting the overall sero-prevalence of 20.5%. There was significant association between different districts (p < 0.05) and PRRS prevalence. Prevalence of PRRSV antibody was found higher in Kaski district (10.5%) followed by Sunsari (8.8%) district. Based on age groups, highest prevalence was found in age groups of above 18 months (9.4%), followed by 13-18 months age groups (7.7%). Regarding the knowledge level of the disease, 43% of the farmers responded that they have heard about the disease. Biosecurity practices in the farm was found very poor where only 40% of the farms had disinfectant at the entrance of the farm and 25% pig farmers were found using separate boots while dealing with pigs.

CONCLUSIONS

The findings of this study reveal the presence of PRRSV antibodies in pigs of Nepal. In addition poor biosecurity measures, management practices and poor knowledge level about the disease among farmers highly affect in the control and prevention of disease thereby affecting the pig production and productivity. Therefore, government should develop and implement effective control measures and biosecurity programs.

Seropositivity of Chlamydia trachomatis & Toxoplasma gondii among male partners of infertile couples in Odisha, India: A facility-based exploratory study

Chlamydia trachomatis (CT) is the most common curable sexually transmitted non-viral infection, which can cause urethritis, prostatitis, orchitis and epididymitis among males. Toxoplasma gondii, a protozoan causes toxoplasmosis among humans. These infections may lead to decreased fertility. Hence, this study was aimed to estimate the seropositivity of CT and T. gondii infection among the male partners of infertile couples in Odisha, India. In this facility-based cross-sectional study, first void urine, seminal fluid and blood sample were collected from 153 males attending infertility clinics including 74 healthy controls. Urine and seminal fluid were tested through polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay was used to detect immunoglobulin (Ig) G, IgA and IgM anti-Chlamydia and IgM anti-Toxoplasma antibodies through serum. The prevalence of CT was 1.26 per cent (95% CI: 0.03-6.85) as estimated from semen samples using PCR. We detected anti-Chlamydia antibodies IgM-four per cent [95% confidence interval (CI): 0.83-11.24]; IgA-28.16 per cent (95% CI: 18.13-40.09) and IgG-12.5 per cent (95% CI: 5.87-22.4) among participants. Anti-Toxoplasma antibodies IgM were observed in 27.63 per cent (95% CI: 17.98-39.08) of participants. None of the control samples were found positive. Overall seropositivity of CT and Toxoplasma infections is comparable, which suggests that greater attention is required for screening these infections at clinics, especially among infertile couples.

Seroprevalence of Bluetongue Virus Antibodies in Ovine in Maji District of West Omo Zone, Southwest Ethiopia

BACKGROUND

Bluetongue (BT) disease is an arthropod-transmitted viral disease of domestic and wild ruminant species caused by Bluetongue virus (BTV). It is of most importance in sheep and endemic primarily in the tropical and subtropical regions where vectors (Culicoides species) are present.

MATERIALS AND METHODS

A cross-sectional study was conducted in July-November 2019 to examine the seroprevalence of BTV infection in ovine in Maji district of West Omo zone. Serum samples were examined for the presence of specific antibodies of BTV using competitive enzyme-linked immunosorbent assay (c-ELISA) test. The collected data was coded and analyzed using STATA version 13 software. Associations between sero-prevalence and its risk factors were tested in a Chi-square analysis and with a P<0.05 were considered as statistically significant.

RESULTS

The individual animal prevalence was revealed as 39.23% (153/390). Herd size prevalence was: small size herd (37.42%; 61/163), medium size herd (32.35%; 55/170), and large size herd (64.91%; 37/57). Species-based prevalence showed ovine (38.00%; 141/371) and caprine (63.15%; 12/19). Age-based prevalence revealed adult (39.26%; 150/382) and young (37.5%; 3/8). The cumulative sex prevalence for both ovine and caprine was male (37.95%; 52/137) and female (39.92%; 101/253).

CONCLUSION

The current prevalence of BTV antibodies in the area was found to be high. Lack of application of bluetongue disease control mechanisms like vaccination for the animals is a key factors for the high prevalence of the disease in the areas besides the existence of the vectors.

COVID-19 Sero-Prevalence and Risk Factors in a Sample of Community Health Center Employees in New York State

OBJECTIVE

To document COVID-19 sero-prevalence, prior testing, symptom experiences, and risk factors in a sample of community health center (CHC) workers.

METHODS

Descriptive statistics and log-binomial regression were used to analyze an electronic employee survey linked with COVID-19 antibody results. The sample included 378 employees who completed the survey; 325 had complete lab data.

RESULTS

The sero-positivity rate was 15.4%. One third of sero-positive participants had no previous COVID-19 symptoms or were unsure. Working on-site only and/or with direct patient contact was not associated with sero-positivity. Employees in their 20s were more likely to test positive than employees ages 50+, controlling for sex, race, and region (PR = 2.96; P < 0.05).

CONCLUSIONS

With CHCs central to COVID-19 response and vaccination efforts, public health messaging should remind CHC workers, especially younger employees, of their risks of community-based exposure.

Changes in epidemiological characteristics and sero-prevalence against the varicella zoster virus in school-age children after the introduction of a national immunization program in Japan

A national immunization program using two doses of live attenuated varicella vaccine was introduced for children aged one to two years in Japan in October 2014. Varicella cases declined after 2014, and immunological status against varicella among vaccinated children changed in post-vaccination era. A retrospective observational study of anti-varicella antibody seroprevalence, varicella vaccination status, and history of varicella among 528 students in the first grade of elementary school was conducted. The percentage of students who received at least a single dose of varicella vaccination increased from 67% (187 of 279 students) in 2007-2008 to 91% (226 of 249 students) in 2017. Students with a history of varicella decreased from 114 of 279 (41%) in 2007-2008 to 48 of 249 (19%, P < .01) in 2017. Among them, the rate of breakthrough varicella after a single dose of vaccine in students with a history of varicella significantly increased from 38% (43 of 114 students) in 2007-2008 to 58% (28 of 48 students) in 2017 (P < .05). The antibody-positive rate significantly decreased from 50% among subjects without varicella zoster who received a single dose (95%CI: 41-58%) in 2007-2008 to 29% (95%CI: 21-38%) in 2017 (P < .01). The antibody-positive rate among students without varicella history who received two doses of vaccine was only 43% (95%CI: 32-55%) in 2017. The number of varicella infections and antibody-positive rate among students without history of varicella who received varicella vaccination decreased after the introduction of a national immunization program.

Sero-prevalence and risk factors of Brucella presence in farm bulk milk from open and zero grazing cattle production systems in Rwanda

BACKGROUND

Animal and human brucelloses have been reported in Rwanda, human brucellosis being linked to drinking inadequately heat-treated milk. However, information on Brucella detection and prevalence in milk produced in Rwanda is limited.

OBJECTIVES

To determine the sero-prevalence and risk factors of Brucella in farm bulk milk from zero and open grazing cattle production systems in Rwanda.

METHODS

A total of 330 farm bulk milk samples were collected from 198 zero grazing farms and 132 open grazing farms in a cross-sectional study in Rwanda. Sero-prevalence of Brucella in milk was analysed using indirect enzyme-linked immunosorbent assay. A questionnaire was administered to farmers to determine the risk factors of milk contamination with Brucella.

RESULTS

Anti-Brucella antibodies were prevalent in 19.7% (95% confidence interval (CI), 15.5-24.4) of the 330 collected farm bulk milk. Sero-prevalence was significantly higher (p < 0.05) in open grazing farms (37.9% [50/132]) than in zero grazing farms (7.6% [15/198]). Practising open grazing system (odds ratio, OR = 69.5; 95% CI = 1.6-3033.6), history of abortion (OR = 19.5; 95% CI = 8.1-46.8) and placenta retention (OR = 4.2; 95% CI = 1.7-10.3) were the significant risk factors for the presence of anti-Brucella antibodies in milk.

CONCLUSION

Notably, more than a third of farm bulk milk from open grazing farms in Rwanda contains Brucella antibodies. Considering the zoonotic nature of Brucella, there is a need to reinforce brucellosis control programs in the country.

Sero-Prevalence of Hepatitis B Virus Infection and Associated Factors Among Pregnant Women Attending Antenatal Care Services in Gedeo Zone, Southern Ethiopia

Background:

Hepatitis B virus infection is a major public health problem worldwide and is a major cause of morbidity and mortality. This study aimed to assess the prevalence of hepatitis B virus infection and associated factors among pregnant mothers in the Gedeo Zone, southern Ethiopia.

Methods:

An institution-based cross-sectional study was conducted among 479 pregnant women visiting governmental and private health facilities in the Gedeo zone from January to April 2019. We selected study participants using systematic random sampling techniques. The Eugene strip test was used to determine hepatitis B virus infection among pregnant mothers. We collected the status of HIV of the pregnant women from the records. Other variables were collected from the mothers using interviewer-administered questionnaires. We used binary and multivariable logistic regression for the analysis. An adjusted odds ratios and their 95% confidence intervals (CIs) were calculated to determine the association between HBsAg sero-positivity and various factors. A P-value of less than .05 was considered significant.

Results:

This study revealed that the prevalence of hepatitis B virus infection among pregnant mothers was 9.2% in Gedeo Zone. A previous history of blood transfusion [AOR = 5.2, 95% CI: 2.1, 12.5], a previous history of hospital admission [AOR = 3, 95% CI: 1.4, 6.6], a history of having an abortion [AOR = 4.1, 95 % CI: 1.5, 11.7], the age of the pregnant women [AOR = 5.1, 95 % CI: 1.5, 18.0], and their HIV status [AOR = 8.1, 95 % CI: 1.9, 36.0] had a statistically significant association with HBsAg sero-positivity.

Conclusion:

Hepatitis B virus infection was found to have higher endemicity (9.2%) in Gedeo Zone which is higher than the national pooled prevalence which was 4.75%. The health facilities must implement early initiation of antenatal care services which incorporate the prevention and control of HBV in the Gedeo Zone.

SARS-CoV-2 outbreak in a synagogue community: longevity and strength of anti-SARS-CoV-2 IgG responses

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic is still ongoing along with the global vaccination efforts against it. Here, we aimed to understand the longevity and strength of anti-SARS-CoV-2 IgG responses in a small community (n = 283) six months following local SARS-COV-2 outbreak in March 2020. Three serological assays were compared and neutralisation capability was also determined. Overall 16.6% (47/283) of the participants were seropositive and 89.4% (42/47) of the IgG positives had neutralising antibodies. Most of the symptomatic individuals confirmed as polymerase chain reaction (PCR) positive during the outbreak were seropositive (30/32, 93.8%) and 33.3% of the individuals who quarantined with a PCR confirmed patient had antibodies. Serological assays comparison revealed that Architect (Abbott) targeting the N protein LIASON^® (DiaSorin) targeting the S protein and enzyme-linked immunosorbent assay (ELISA) targeting receptor binding domain detected 9.5% (27/283), 17.3% (49/283) and 17% (48/283), respectively, as IgG positives. The latter two assays highly agreed (kappa = 0.89) between each other. In addition, 95%, (19/20, by ELISA) and 90.9% (20/22, with LIASON) and only 71.4% (15/21, by Architect) of individuals that were seropositive in May 2020 were found positive also in September. The unexpected low rate of overall immunity indicates the absence of un-noticed, asymptomatic infections. Lack of overall high correlation between the assays is attributed mainly to target-mediated antibody responses and suggests that using a single serological assay may be misleading.

Insights from a Pan India Sero-Epidemiological survey (Phenome-India Cohort) for SARS-CoV2

To understand the spread of SARS-CoV2, in August and September 2020, the Council of Scientific and Industrial Research (India) conducted a serosurvey across its constituent laboratories and centers across India. Of 10,427 volunteers, 1058 (10.14%) tested positive for SARS-CoV2 anti-nucleocapsid (anti-NC) antibodies, 95% of which had surrogate neutralization activity. Three-fourth of these recalled no symptoms. Repeat serology tests at 3 (n = 607) and 6 (n = 175) months showed stable anti-NC antibodies but declining neutralization activity. Local seropositivity was higher in densely populated cities and was inversely correlated with a 30-day change in regional test positivity rates (TPRs). Regional seropositivity above 10% was associated with declining TPR. Personal factors associated with higher odds of seropositivity were high-exposure work (odds ratio, 95% confidence interval, p value: 2.23, 1.92-2.59, <0.0001), use of public transport (1.79, 1.43-2.24, <0.0001), not smoking (1.52, 1.16-1.99, 0.0257), non-vegetarian diet (1.67, 1.41-1.99, <0.0001), and B blood group (1.36, 1.15-1.61, 0.001).

Serosurvey of Avian Influenza Viruses (H5, H7, and H9) and Associated Risk Factors in Backyard Poultry Flocks of Lahore District, Pakistan

Rural poultry constitutes 56% of the total poultry population in Pakistan; however, epidemiological information about avian influenza viruses (AIVs) in backyard poultry flocks is lacking. A cross-sectional survey of villages of Lahore district was conducted from July 2009 to August 2009 using two-stage cluster sampling and probability proportional to size (PPS) sampling to estimate seroprevalence and its associated risk factors. A random selection of 35 clusters from 308 villages of Lahore were considered, and from each cluster, six chickens aged >2 months were selected. A total of 210 serum samples were collected and examined by the hemagglutination inhibition (HI) test for specific antibodies against AIV subtypes H5, H7, and H9. Overall weighted seroprevalence for AIVs was 65.2% (95% CI: 55.6–74.8%), and for subtype H5, H7 & H9 was 6.9% (95% CI: 10.8–23.0%), 0% (95% CI: 0–1.7%), and 62.0% (95% CI: 52.2–71.8%) respectively. However, none of the samples were positive for H7. The average flock size was 17.3 birds, and the main purpose of keeping poultry was for eggs/meat (70.6%, 95% CI: 59.7–81.4). A majority of them were reared in a semi-caged system (83%, 95% CI: 74.5–91.3). Backyard birds were received from different sources, that is, purchased from the market or received as a gift from friends or any NGO, and were 5.7 times more likely to become avian influenza (AI) seropositive than those that were not exposed to these sources (CI 95%: 2.0–716.0). Backyard birds which were received from different sources, that is, purchased from the market or received from friends or any NGO, were 5.7 times more likely to become AI seropositive compared to those that were not (CI 95%: 2.5–18.7). To reduce the risk of AIV in Pakistan, continuous surveillance of backyard poultry would be needed.

Occurrence of Antibodies against SARS-CoV-2 in the Domestic Cat Population of Germany

Domestic cats (Felis catus) are popular companion animals that live in close contact with their human owners. Therefore, the risk of a trans-species spreading event between domestic cats and humans is ever-present. Shortly after the emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its rapid spread around the world, the role of domestic cats in the transmission cycle was questioned. In the present study, the first large-scale survey of antibody occurrence in the domestic cat population in Germany was conducted, in order to assess the incidence of naturally occurring human to cat transmission of SARS-CoV-2. A total of 920 serum samples, which were collected from April to September of 2020, were screened by an indirect multispecies ELISA. Positive samples were verified using an indirect immunofluorescence test (iIFT) and additionally tested for neutralizing antibodies. Furthermore, serum samples were screened for antibodies against feline coronavirus (FCoV), in order to rule out cross-reactivity in the described test systems. Overall, 0.69% (6/920) of serum samples were found to be positive for antibodies against SARS-CoV-2 by ELISA and iIFT. Two of these reactive sera also displayed neutralizing antibodies. No cross-reactivity with FCoV-specific antibodies was observed. The finding of SARS-CoV-2 antibody-positive serum samples in the domestic cat population of Germany, during a period when the incidence of human infection in the country was still rather low, indicates that human-to-cat transmission of SARS-CoV-2 happens, but there is no indication of SARS-CoV-2 circulation in cats.

Association of PPE Availability, Training, and Practices with COVID-19 Sero-Prevalence in Nurses and Paramedics in Tertiary Care Hospitals of Peshawar, Pakistan

Objective:

Nurses and paramedics by being the frontline workers of the health-care profession need to be equipped with the relevant knowledge, skills, and protective gears against different forms of infection, including coronavirus disease 2019 (COVID-19). Although the governments and concerned stakeholders have provided personal protective equipment (PPE), training and information to protect the health-care professionals; however, until now the scientific literature has virtually not reported the impact of PPE availability, training, and practices on the COVID-19 sero-prevalence among the nurses and paramedics. This study aimed to assess the impact of PPE availability, training, and practices on COVID-19 sero-prevalence among nurses and paramedics in teaching hospitals of Peshawar, Pakistan.

Methods:

A cross-sectional survey was conducted with a total of 133 nurses and paramedics as subjects of the study.

Results:

A univariate analysis was done for 4 variables. The findings indicate that the health-care professionals (nurses and paramedics) who have received PPE on time at the start of COVID-19 emergence have fewer chances of contracting the COVID-19 infection (odds ratio = 0.96); while the odds for PPE supplies was 0.73, and the odds of hand hygiene training was 0.95.

Conclusions:

The study concluded that the availability of the PPE, COVID-19–related training, and compliance with World Health Organization recommended practices against COVID-19 were instrumental in protection against the infection and its spread.

Association of Hantavirus Infections and Leptospirosis With the Occurrence of Chronic Kidney Disease of Uncertain Etiology in the North Central Province of Sri Lanka: A Prospective Study With Patients and Healthy Persons

Chronic Kidney disease of uncertain etiology (CKDu) has become a significant disease burden, affecting farming community of Sri Lanka and the exact etiology, which could be multifactorial, is not hitherto established. This study is aimed to determine the association of past hantavirus infection and leptospirosis with the occurrence of CKDu. A cohort (n = 179) of known CKDu patients living in high-CKDu prevalent areas of Anuradhapura district of Sri Lanka was compared with a group of 49 healthy, sex-matched younger blood relatives of CKDu patients (control-1) and another 48 healthy, age, and sex-matched individuals living in low-CKDu prevalent area (control-2) of the same district where same life style and climate conditions prevail. Fifty out of 179 (27.9%) CKDu patients, 16/49 (32.7%) of control-1 and 7/48 (14.6%) of control-2 were found positive for IgG antibodies to Puumala, Hantaan or both strains of hantaviruses. Hantaan strain specificity was found to be predominant in all study groups. Hantavirus IgG sero-prevalence of healthy individuals living in low-CKDu prevalent area was significantly lower compared to CKDu patients and healthy younger blood relatives living in high-CKDu prevalent areas (p = 0.03). Past hantavirus infection possesses a significant risk for the occurrence of CKDu (OR = 4.5; 95% CI-3.1-5.4, p = 0.02). In contrast, IgG seroprevalence to hantaviruses was not significantly different in CKDu patients and healthy younger blood relatives living in high-CKDu prevalent areas indicating past hantavirus infection has no association with the occurrence of CKDu or possibly, younger relatives may develop CKDu in subsequent years. Seroprevalence to leptospirosis showed no significant difference between CKDu patients and healthy controls.

Estimating the Percentage of a Population Infected with SARS-CoV-2 Using the Number of Reported Deaths: A Policy Planning Tool

The magnitude of future waves of Covid19 in a population will depend, in part, on the percentage of that population already infected, recovered, and presumably immune. Sero-epidemiological surveys can define the prevalence of SARS-CoV-2 antibodies in various populations. However, sero-surveys are resource-intensive and methodologically challenging, limiting widespread use. We propose a relatively simple method for calculating the percentage of a population infected, which depends on the number of reported Covid19 deaths, a figure usually more reliable and less dependent on variable testing practices than the total number of reported Covid19 cases, and the infection fatality rate, a figure that is relatively stable in similar populations. The method can be applied in different sized areas, such as states, districts, or cities. Such an approach can provide useful, real-time estimates of probable population immunity in settings unable to undertake multiple sero-surveys. This method is applicable to low- and lower-middle-income country (LMIC) settings where sero-survey data will likely be limited; however, better estimates of infection fatality rates and Covid19 death counts in LMICs are needed to improve the method's accuracy. Information on the percentage of a population infected will help public health authorities in planning for future waves of Covid19, including where to most effectively deploy vaccines.

Serological Evidence of Avian Influenza in Captive Wild Birds in a Zoo and Two Safari Parks in Bangladesh

Avian influenza (AI) is endemic and frequently causes seasonal outbreaks in winter in Bangladesh due to high pathogenic avian influenza (HPAI) H5N1 and low pathogenic avian influenza (LPAI) H9N2. Among avian influenza A viruses (AIV), H5, H7, and H9 subtypes have the most zoonotic potential. Captive birds in zoos and safari parks are used for educational, recreational, breeding, and conservational purposes in Bangladesh. To screen for AIV in captive birds to assess potential public health threats, we conducted a cross-sectional study in two safari parks and one zoo in Bangladesh for four months, from November to December 2013 and from January to February 2014. We collected blood samples, oropharyngeal, and cloacal swabs from 228 birds. We tested serum samples for AIV antibodies using competitive enzyme-linked immunosorbent assay (c-ELISA) and AIV sero-subtype H5, H7, and H9 using hemagglutination inhibition (HI) test. Swab samples were tested for the presence of avian influenza viral RNA using real-time reverse transcription-polymerase chain reaction (rRT-PCR). Across all the samples, AIV antibody prevalence was 9.7% (95% CI: 6.1-14.2, n = 228) and AIV HA subtype H5, H7 and H9 sero-prevalence was 0% (95% CI: 0-1.6, n = 228), 0% (95% CI: 0-1.6, n = 228) and 6.6% (95% CI: 3.72-10.6, n = 228), respectively. No AI viral RNA (M-gene) was detected in any swab sample (0%, 95% CI: 0-1.6, n = 228). Birds in the Safari park at Cox's Bazar had a higher prevalence in both AIV antibody prevalence (13.5%) and AIV H9 sero-prevalence (9.6%) than any of the other sites, although the difference was not statistically significant. Among eight species of birds, Emu (Dromaius novaehollandiae) had the highest sero-positivity for both AIV antibody prevalence (26.1%) and AIV H9 prevalence (17.4%) followed by Golden pheasant (Chrysolophus pictus) with AIV antibody prevalence of 18.2% and AIV H9 prevalence of 11.4%. Our results highlight the presence of AI antibodies indicating low pathogenic AIV mingling in captive birds in zoos and safari parks in Bangladesh. Continuous programmed surveillance is therefore recommended to help better understand the diversity of AIVs and provide a clear picture of AI in captive wild birds, enabling interventions to reduce the risk of AIV transmission to humans.

HIV prevalence among people who inject drugs (PWID) and related factors in Iran: a systematic review, meta-analysis and trend analysis

AIMS

In Iran, injecting drug use has been the major route of human immunodeficiency virus (HIV) transmission. In order to control the HIV epidemic, a harm reduction program was initiated and has been expanded in recent years. The aim of this study was to provide an updated estimate of HIV prevalence among people who inject drugs (PWID) in Iran, investigate prevalence differences over time and assess prevalence correlates.

DESIGN

A comprehensive systematic review was undertaken in the international, regional and national bibliographic databases in November 2018 and extensive contacts with authors were made. For studies conducted before 2005, we used data from a previous published systematic review.

SETTING

All studies conducted in Iran were included. Recruitment settings included anywhere except studies conducted in infectious diseases wards or HIV counseling centers.

PARTICIPANTS

PWID with any definition utilized in the studies. Thirty-six studies were included, which were conducted in 24 of 31 provinces with a sample size of 22 160 PWID.

MEASUREMENTS

We included studies that had performed HIV testing and had a confirmed diagnosis of HIV through repeating the enzyme-linked immunosorbent assay (ELISA) or Western immunoblot assay (WB). Pooled prevalence of HIV was calculated for the total sample and for different subgroups, by available socio-demographic and behavioral factors. For assessing the trend of HIV prevalence over time, a linear meta-regression model was fitted separately for before 2007 and during 2007 and afterwards.

FINDINGS

The pooled prevalences of HIV before 2007 and in 2007 and afterwards were 14.3% [95% confidence interval (CI) = 9.8-18.9] and 9.7% (95% CI = 7.6-11.9), respectively. HIV prevalence increased until 2005-06 and then slowly declined until 2009-10, which was not significant. Prevalence of HIV was significantly higher in PWID above age 25 years, and in those with history of imprisonment and history of needle/syringe-sharing. HIV prevalence was higher in men than in women, but the difference was insignificant.

CONCLUSION

The prevalence of HIV among people who inject drugs in Iran decreased after 2006 which could, at least in part, be attributed to the development of extensive harm reduction programs in the country.

Epidemiological investigation and phylogenetic analysis of caprine parainfluenza virus type 3 in sheep of China

Caprine parainfluenza virus type 3 (CPIV3) is a new member of the Respirovirus genus in the Paramyxivirudae family, mainly causing respiratory disease. Up to now, accumulating evidence has focused on CPIV3 infection in goats, with little understood about its epidemiology in sheep. To that end, we collected 1,163 sheep sera samples from nine provinces/autonomous regions in 2012 and 1,863 samples from six provinces/autonomous regions during 2016-2017, with serological prevalence of 50.3% (95% CI: 47.5, 53.3) and 64.9% (95% CI: 62.9, 67.2), respectively. Pathogenic detection by qRT-PCR was also performed on serum samples collected in 2016-2017, and the percentage of CPIV3 positive samples was 21.5% (95% CI: 19.7, 23.5). Sequence alignment and phylogenetic analyses revealed 11 novel CPIV3 strains based on the M gene sequences. The M gene and full-length sequences of CPIV3 strains derived from sheep shared high nucleotide similarity with goat-origin strains, indicating conserved genome characteristics between the viruses. Furthermore, sequence evolution and epidemiological analysis show that CPIV3 is widespread throughout China. This is the first report describing CPIV3 infection in sheep in China, showing a high sero-prevalence and contributes to the assessment of the epidemiology of CPIV3 in China.

Molecular characterization of Peste des petits ruminants viruses in the Marmara Region of Turkey

Recent outbreaks of Peste des petits ruminants (PPR) in the Marmara region of Turkey including the European part of Thrace is important due to its proximity to Europe (Greece and Bulgaria) and the potential threat of spread of PPR into mainland Europe. In order to investigate the circulation of PPRV in the region suspect clinical and necropsy samples were collected from domestic sheep (n = 211) in the Marmara region of Turkey between 2011 and 2012. PPR virus (PPRV) genome was detected in 10.4% (22 out of 211) of sheep samples by real-time RT-PCR, and PPR virus was isolated from lungs of two sheep that died from infection. Of the 22 positive samples nine were used for partial N-gene amplification and sequencing. The phylogenetic analyses indicated that the virus belongs to lineage IV, the same lineage that is circulating in eastern and central part of Turkey since its first official report in 1999. In addition, samples from 100 cattle were collected to investigate potential subclinical circulation of PPRV. However all were found to be negative by real-time RT-PCR, and also in serological tests indicating the large ruminants were likely not exposed or infected with the virus. The impact of these findings on the potential threat of spread of PPR to Europe including the first PPR outbreak in Europe in Bulgaria on 23rd June 2018 is discussed.

Rubella virus infection and associated factors among pregnant women attending the antenatal care clinics of public hospitals in Hawassa City, Southern Ethiopia: a cross-sectional study

OBJECTIVE

To assess the seroprevalence of recent/acute and past exposure to rubella virus infection and associated risk factors among pregnant women.

DESIGN

A hospital-based cross-sectional study.

SETTING

The study was conducted in two public hospitals in Hawassa City, Southern Ethiopia.

PARTICIPANTS

A total of 422 pregnant women attending antenatal care clinics were selected using a systematic random sampling technique from March to June 2016.

OUTCOME MEASURES

Data on sociodemography and related factors were collected using a structured questionnaire. Blood samples were also collected from each study participant and tested for antirubella IgM and IgG antibodies using ELISA. IgG seropositivity indicates past exposure to rubella (protective immunity). IgM seropositivity indicates recent exposure to rubella (or reinfection).

RESULTS

The seroprevalence of antirubella IgM and IgG antibodies was 2.1% and 86.3%, respectively. Thus, the rate of susceptibility to rubella virus infection among pregnant women was found to be 13.7%. A significant association between residence site and IgG seropositivity was observed, where urban dwellers had higher past rubella exposure compared with rural residents (crude OR 6.3; 95% CI 3.29 to 12.14, p<0.001).

CONCLUSION

The high rate of rubella exposure and its similar distribution by sociodemography (except residence site) suggests the continuous transmission and endemicity of the infection in the study area. These findings emphasise the importance of introducing rubella-containing vaccine into routine childhood immunisation programme and vaccinating susceptible women of childbearing age.

Sero-prevalence and epidemiology of peste des petits ruminants in Libya

We conducted a cross-sectional study during 2013 to quantify the serological prevalence of peste des petits ruminants (PPR) infection and to investigate host factors associated with PPR infection in small ruminants in Libya. A two-stage sampling design was carried out. A total number of 148 flocks owning at least 100 heads each were randomly selected. Sixteen to forty-eight samples were collected from each selected flock. A total number of 3,508 serum samples from unvaccinated animals were collected and analysed at IZSLER Brescia, Italy, by using competitive ELISA, IDvet innovative diagnostics (IDvet 310, France). The overall serological prevalence among SR was 33% (95% CI: 31.4-34.5). Significant differences between the prevalence in the geographical branches were observed. The lowest prevalence level was observed in Zawiyah branch (16.1%), whereas the highest value was obtained for the Sabha branch (56.8%). Considering the age, a serological prevalence of 24.7%, 31.5% and 42.1% was observed in SR <1 year, between 1 and 2 years and more than 2 years, respectively. Statistically significant differences (p < .001) in the sero-prevalence levels were also observed between the age groups. Our findings suggest that the southern part of Libya could be more exposed to the infections coming from the neighbouring countries and this should be better investigated to correctly identify wherever specific entry points can be considered at higher risk than others. The results also confirmed the endemic status of PPR in Libya, with a constant exposure to the infection of the animals during their life. In the framework of the global strategy for control and eradication of PPR, our results, even if obtained by a preliminary study, can contribute to the assessment of the epidemiological situation of PPR in Libya as required by the Stage 1 of the plan.

[The analysis of sero-prevalence of virus of hepatitis E among patients with HIV-infection and syphilis.]

The infection with hepatitis E virus is one of causes of liver diseases in patients with secondary immunodeficiency, including HIVinfected ones. The study was carried out concerning analysis of rate of detection of serological markers of infection with hepatitis E virus in samples of blood serums of HIV-infected patients and other group of patients with expressed immuno-suppression - patients with syphilis. The sero-prevalence of hepatitis E virus on IgM-antibodies among HIV-infected patients in Moscow made up to 21.7% and 2.9% correspondingly. In the examined group from the Far-East region the highest sero-prevalence of hepatitis E virus on specific IgE-antibodies (73%) is established in the group of patients infected with HIV subtype B. The most frequently IgG and IgM antibodies to hepatitis E virus were detected in HIV-infected patients at the stage of disease 4B. The examined group of patients with syphilis the sero-prevalence of hepatitis E virus made up to 14.7% that significantly surpasses the given indicator in the group of healthy persons (1.7%). The increasing of the level of sero-postivity is demonstrated in the groups of patients with latent syphilis and on the second stage of disease. Therefore, the highest values of sero-prevalence of hepatitis E virus is observed in the groups of HIV-infected patients and patients with syphilis at late stages of disease. In the Russian Federation, the identification of antibodies to hepatitis E virus in HIV-infected patients depends of the region of residence.

Socio-demographic and behavioural characteristics associated with HSV-2 sero-prevalence in high risk women in KwaZulu-Natal

BACKGROUND

The World Health Organization estimates that 536 million people aged 15-49 are infected with Herpes simplex virus type 2 (HSV-2), the causative agent of genital herpes. The aim of this study was to investigate the role of behavioral and demographic factors that contribute to the high HSV-2 sero-prevalence among women participating in a HIV prevention trial. The Methods for Improving Reproductive Health in Africa (MIRA) study assessed the effectiveness the latex diaphragm and lubricant gel on HIV prevention among women in South Africa and Zimbabwe. At screening an interviewer administered questionnaire on demographics and sexual behaviour was obtained. HSV-2 serum antibodies were detected using HerpeSelect™ ELISA IgG. Statistical analysis was performed using STATA release 12.0. This study was registered with ClinicalTrials.gov,number NCT00121459 on the 28th February 2007.

FINDINGS

Of the 3 472 women screened at the Durban research sites 2 218 (73%) had a prevalent HSV-2 infection and 1431 (41%) of the women were also co-infected with HIV. In the multivariate analyses, older women (adjusted odds ratio) [aOR]: 3.49, 95% CI: (2.71,4.49) for >35 years and aOR: 1.82, 95% CI: 1.49, 2.22 for 25-34 years compared with <25 years, p < 0.001 for both comparisons were more likely to be HSV-2 sero-positive. Low level of education (OR: 1.26 95% CI: 1.03, 1.53), having >1 life-time sexual partners (OR: 2.48, 95% CI: 1.92, 3.20), parity >1 (OR: 1.95 95% CI: 1.92, 3.20) and being HIV positive (OR: 6.31, 95% CI: 5.06, 7.88) were significantly associated with HSV-2 infection.

CONCLUSION

The high sero-prevalence of HSV-2 in the studied population is of great public health importance since this high risk population could act as a reservoir for future infections particularly HIV transmission.

Sero-epidemiology of Peste des petits ruminants virus infection in Turkana County, Kenya

BACKGROUND

Peste des petits ruminants (PPR) is a contagious viral disease of small ruminants. Serum samples from sheep (n = 431) and goats (n = 538) of all ages were collected in a cross-sectional study in Turkana County, Kenya. The objective was to estimate the sero-prevalence of PPR virus (PPRV) infection and associated risk factors in both species. PPRV competitive enzyme-linked immuno-sorbent assay (c-ELISA) analysed the presence of antibodies in the samples. All analyses were conducted for each species separately. Multivariable logistic regression models were fitted to the data to assess the relationship between the risk factors and PPRV sero-positivity. Mixed-effect models using an administrative sub-location as a random effect were also fitted to adjust for possible clustering of PPRV sero-positivity. Intra-cluster correlation coefficients (ρ) that described the degree of similarity among sero-positive responses for each species in each of the six administrative divisions were estimated.

RESULTS

Goats had a significantly higher sero-prevalence of 40% [95% confidence interval (CI): 36%, 44%] compared to sheep with 32% [95% CI: 27%, 36%] (P = 0.008). Combined sero-prevalence estimates were heterogeneous across administrative divisions (n = 6) (range 22% to 65%) and even more across sub-locations (n = 46) (range 0% to 78%). Assuming that PPRV antibodies are protective of infection, a large pool of PPRV susceptible middle age group (>6 months and < 24 months) in both species was estimated. This was based on the low sero-prevalence in this group in goats (14% [95% CI: 10%, 20%]) and in sheep (18% [95% CI: 13%, 25%]). Regression analysis returned significant risk factors across species: in sheep - vaccination status, age and administrative division; in goats - sex, age, administrative division and sex*age interaction. The intra-sub-location correlation coefficients varied widely across divisions (range <0.001 to 0.42) and across species within divisions.

CONCLUSIONS

Biological, spatial and socio-ecological factors are hypothesized as possible explanations for variation in PPRV sero-positivity in the Turkana pastoral ecosystem.

Rethinking HIV prevalence determination in developing countries

The process for HIV prevalence determination using antenatal clinic (ANC) sentinel surveillance data has been plagued by criticisms of its biasness. Exploring other means of HIV prevalence determination is necessary to validate that estimates are near actual values or to replace the current system. We propose a data collection model that leverages the increasing adoption and penetration of the Internet and mobile technology to collect and archive routine data from HIV counseling and testing (HCT) client intake forms from all HCT centers and prevention of mother-to-child transmission (PMTCT) sites in a country. These data will then be mined to determine prevalence rates and risk factors at the community level. The need to improve the method for the generation of HIV prevalence rates has been repeatedly echoed by researchers though no one has been able to fashion out a better and more reliable way to the current ANC sentinel surveillance method at a reasonable cost. The chance of using routinely generated data during HCT and PMTCT is appealing and needs to be envisioned as the technology to achieve this is increasingly becoming available and affordable in countries worst hit by the pandemic. Triangulating data generated from routine HCT and PMTCT sites with data from sentinel surveillance and where the confidence of its quality is assured, as the sole source of HIV prevalence rate determination and behavioral risk assessment will improve the acceptance by communities and drive evidence-based interventions at the community level.

HIV-1/HIV-2 co-infection among voluntary counselling and testing subjects at a regional hospital in Cameroon

BACKGROUND

HIV/AIDS is a major public health problem in Cameroon which had a prevalence of 5.1% in 2010 with 141 new infections per day. The fear of voluntary counseling and testing (VCT) is an obstacle to HIV prevention.

OBJECTIVES

To determine the prevalence of HIV-1, HIV-2 and HIV-1/HIV-2 co-infection among people attending a health facility for VCT.

METHODS

Venous blood was collected from participants using aseptic techniques in a descriptive observational cross-sectional study. DETERMINE HIV-1/2 and SD BIOLINE HIV-1/2 3.0 qualitative tests were used for the detection of HIV-1 and HIV-2 in their sera. Range and consistency checks were carried out on the data and analysed using Epi-Info.

RESULTS

Of 290 individuals tested, 78(26.9%) were positive for HIV-1 and HIV-2. Among the 78 HIV positive individuals, 62 (79.5%) had HIV-1, 1(1.3%) had HIV-2 and 15(19.2%) had concurrent HIV-1/ HIV-2. Among those infected, 57(73.1%) were females including 21(26.9%) males.

CONCLUSION

HIV-1 is the major cause of AIDS and VCT is well accepted. Co-infection with HIV-1/HIV-2 may lead to anti-retroviral drug resistance. VCT should be encouraged so that positive cases can initiate therapy on time to stay ahead of anti-retroviral drug resistance.

Evidence of peste des petits ruminants in serology of sheep and goats from Sindh, Pakistan

The following is the first detailed description of laboratory confirmed evidence of peste des petits ruminant virus (PPRV) in 14 districts of Sindh province, Pakistan. Sindh is the 2nd largest province of Pakistan in terms of human population and livestock. Livestock are the main origin of the people's livelihood. Samples were collected during the surveillance programme from sheep and goats showing severe respiratory signs and mouth lesions. Competitive enzyme-linked immuno-sorbant assay (cELISA) was performed to detect the presence of antibodies in the serum against PPRV. Findings suggested that the overall PPR sero-prevalence in sheep was 49.5% when compared to goats, which was 56.3%. As we observed during an 18 months' period, most of the cases that occurred emerged with the start of hot season and peaked during the months of April, May, June and July, and then the prevalence dropped. Among various age groups, the animals that showed the higher prevalence of antibodies to PPRV were >2 years. In the age group <1 year, there was a significant difference in the prevalence which was 48.6% in goats when compared to 32.1% in sheep. Similarly, it was the same in the second age group (1-2 years), 46.9% in sheep when compared to 55.3% goats. There was little variation in the third age group (>2 years), being around 61.7% in goats when compared to 63.4% in sheep. The highest sero-prevalence was in Tharparkar followed by Mirpur Khas and Tando Allahyar. The study indicated the scenario of PPRV circulation in the population of the two domestic ruminant species (sheep and goats) with frequent disease outbreaks.