Case of Poliomyelitis Caused by Significantly Diverged Derivative of the Poliovirus Type 3 Vaccine Sabin Strain Circulating in the Orphanage

Significantly divergent polioviruses (VDPV) derived from the oral poliovirus vaccine (OPV) from Sabin strains, like wild polioviruses, are capable of prolonged transmission and neuropathology. This is mainly shown for VDPV type 2. Here we describe a molecular-epidemiological investigation of a case of VDPV type 3 circulation leading to paralytic poliomyelitis in a child in an orphanage, where OPV has not been used. Samples of feces and blood serum from the patient and 52 contacts from the same orphanage were collected twice and investigated. The complete genome sequencing was performed for five polioviruses isolated from the patient and three contact children. The level of divergence of the genomes of the isolates corresponded to approximately 9–10 months of evolution. The presence of 61 common substitutions in all isolates indicated a common intermediate progenitor. The possibility of VDPV3 transmission from the excretor to susceptible recipients (unvaccinated against polio or vaccinated with inactivated poliovirus vaccine, IPV) with subsequent circulation in a closed children’s group was demonstrated. The study of the blood sera of orphanage residents at least twice vaccinated with IPV revealed the absence of neutralizing antibodies against at least two poliovirus serotypes in almost 20% of children. Therefore, a complete rejection of OPV vaccination can lead to a critical decrease in collective immunity level. The development of new poliovirus vaccines that create mucosal immunity for the adequate replacement of OPV from Sabin strains is necessary.

Epidemiological serosurvey of poliovirus in Guangdong, China: A cross-sectional study

A cross-sectional study for poliovirus seroprevalence in Guangdong was carried out in 2014, just before a change in polio vaccine commenced in 2015. The aim of the study was to test whether polio immunity level was high enough to satisfy the polio vaccine switch. A total of 6339 people were tested for poliovirus neutralization antibodies (NA). Overall NA seropositivity for PV1, PV2 and PV3 were 95.2%, 94.9% and 88.7%, and the respective geometric mean titer (GMT) were 82.9, 55.8, and 26.3, respectively. There were statistically significant differences in the positive rates and GMT of the 3 serotypes and PV3 had relatively lower positive rates and GMT. The highest seropositivity and GMT were observed in the 1-9 year-old age group. The positive rates of NA and GMT for PV1, PV2 and PV3 in the western region of Guangdong were lower than those of other three regions. The results of this study showed that the population of Guangdong province had a high polio immunity level, a stable base for a polio vaccine switch.

[Collective immunity against poliomyelitis among the population of several regions of Russia]

The goal of this work was to estimate the collective immunity against poliomyelitis among the population of 8 regions and republics of Russia. The rates of the collective immunity against poliomyelitis allow the polio vaccination quality to be estimated and the population protection rate to be simultaneously demonstrated. A total of 8 regions (2138 people) were tested. The antibodies to the polioviruses of 1-3 types were determined against the vaccine Sabin strains in the neutralization test in the RD cell line. As a result, we found that vaccination against poliomyelitis in all observed regions was maintained at the required high level. Thus, the number of people with antibodies to the polio in most regions and age groups approximates or reaches 100%, while GMT is also high. This work demonstrated the necessity of the continuation of vaccination against poliomyelitis and control over collective immunity.

Sero-survey of polio antibodies during wild poliovirus outbreak in southern Xinjiang Uygur Autonomous Region, China

Background

After being polio free for more than 10 years, an outbreak following importation of wild poliovirus (WPV) was confirmed in Xinjiang Uygur Autonomous Region, China, in 2011.

Methods

A cross-sectional study was conducted prior to supplementary immunization activities (SIAs), immediately after the confirmation of the WPV outbreak. In selected prefectures, participants aged ≤60 years old who visited hospitals at county-level or above to have their blood drawn for reasons not related to the study, were invited to participate in our study. Antibody titers ≥8 were considered positive.

Results

Among the 2,611 participants enrolled, 2,253 (86.3%), 2,283 (87.4%), and 1,989 (76.2%) were seropositive to P1, P2 and P3 respectively, and 1744 (66.8%) participants were seropositive to all the three serotypes. Lower antibody seropositivities and geometric mean titers were observed in children <1 year of age and in adults aged 15–39 years.

Conclusion

Serosurveys to estimate population immunity in districts at high risk of polio importation might be useful to gauge underlying population immunity gaps to polio and possibly to guide preparedness and response planning. Consideration should be given to older children and adults during polio risk assessment planning and outbreak response.

[State of collective immunity against poliomyelitis in some regions of Russia]

AIM

Study the state of collective immunity against poliomyelitis in 7 regions of Russia in the last 3 years.

MATERIALS AND METHODS

2579 sera were studied for antibodies against poliomyelitis virus. Antibodies (AT) against 3 types of viruses were determined in neutralization reaction in RD cell culture, the state of collective immunity in the examined individuals was evaluated by the percent of individuals with AT against a type of poliovirus and geometric mean AT titer. The circulation of wild polioviruses was judged by the presence of strain specific AT against wild and vaccine viruses in the examined children (311 sera were studied).

RESULTS

The indicators of collective immunity against poliomyelitis in both select examined regions and select age groups were generally high. The data obtained allow to make a conclusion that the quality of vaccine prophylaxis in the examined regions is good. Introduction of wild poliovirus type 1 from Tajikistan in 2010 caused disease in 7 residents of Russia whereas an epidemic that had affected more than 700 individuals emerged in Tajikistan.

CONCLUSION

The studies carried out confirmed the necessity to continue qualitative poliomyelitis vaccine prophylaxis in the country despite the lack of circulation of wild polioviruses that can be introduced at any time.

[Monitoring of implementation of international programs of poliomyelitis eradication and measles and rubella elimination in the Republic of Belarus]

AIM

Monitoring of implementation of international programs of poliomyelitis eradication, and measles and rubella elimination in the Republic of Belarus based on results of molecular-epidemiologic studies of 2009 - 2010.

MATERIALS AND METHODS

271 viral agents isolated from children with acute flaccid paralysis syndrome, other diseases, healthy children and from sewage water within the framework of poliomyelitis control implementation were identified by serological and molecular methods. Blood sera of 528 patients with fever and rash were examined for the presence of IgM to measles and rubella virus, 418 - for the presence of IgM to parvovirus B19 and parvovirus DNA. Blood sera of 33 pregnant women and 64 children with signs of intrauterine infection were studied for IgM and IgG antibodies to rubella virus. Measles virus was isolated, N-gene sequence and phylogenetic analysis carried out.

RESULTS

The studies performed confirmed that indigenous wild polioviruses in the country do not circulate, imported wild or vaccine-related polioviruses were also not detected. Measles and rubella morbidity in the Republic of Belarus was less than 1 in 1 000 000. 2 cases of rubella (2009) and 1 case of measles (2010) was detected during adequate control level: the rate of detection of patients with fever and rash, in whom measles and rubella diagnosis was excluded by the results of laboratory examination, was more than 2 in 100 000 of the population. The etiologic agent in more than 20% of diseases with fever and rash was parvovirus B19. A single case of measles was caused by genotype D8 virus imported from India.

CONCLUSION

The data obtained give evidence to conformance of the poliomyelitis, measles, rubella, innate rubella syndrome control implemented in the Republic of Belarus to WHO recommendations; maintenance of status of country as free from poliomyelitis and achievement of main criteria of elimination of both measles and rubella by 2010.

[Immunity to poliovirus after vaccination of children with type 1 diabetes mellitus and rheumatic diseases]

AIM

To assess immunization coverage against poliomyelitis and level of immunity postvaccination in children with type 1 diabetes mellitus (DM1) and rheumatic diseases.

MATERIALS AND METHODS

Vaccination status of 299 children with DM1 and 136 children with rheumatic diseases was determined. Serologic test using neutralization reaction was performed in 31 children with DM1 and 29 children with rheumatic diseases. Three hundred and eighty healthy children aged 3-14 years were included in the control group. All children previously received oral poliovirus vaccine.

RESULTS

During postimmunization period decompensations of main disease in children with DM1 and rheumatic diseases were not observed. There were no seronegative children to all poliovirus types revealed. Proportion of children with DM1 and rheumatic diseases seronegative to two serotypes was 12.9% and 13.8% respectively. Proportion of children with DM1 seropositive to all 3 serotypes was 54.8% that is lower than in general population (p<0.01), whereas in children with rheumatic diseases this proportion was 75.8%. In children with DM1 real proportion of immune subjects was normal--94.9% and 82.0% for pqliovirus types 1 and 2 respectively, whereas the same proportion for poliovirus type 3 was 49.7%. In children with rheumatic diseases real proportion of immune subjects was normal for poliovirus types 1 and 2, and was 72.4% for poliovirus type 3.

CONCLUSION

Algorithms of examination of patientswith DM1 and rheumatic diseases, which allow to purposefully perform serologic evaluation as well as recommendations about additional immunization against poliomyelitis, were developed.

[Analysis on poliomyelitis neutralizing antibody in healthy population on border areas of Guangxi Zhuang Autonomous Region]

OBJECTIVE

To understand the antibody level of poliomyelitis in healthy population on border districts of Guangxi Zhuang Autonomous Region.

METHODS

The surveillance of poliomyelitis neutralizing antibody was conducted from a selected randomly stratified sample of 902 border residents who aged from 1- to 59-years-old.

RESULTS

The positive rate and geometric mean titer (GMT) of poliomyelitis neutralizing antibody type I, II and III were 93.90%, 97.67%, 92.02% and 1:53.22, 1:66.51, 1:20.01 respectively.

CONCLUSION

A higher level of immunity against poliovirus in healthy population has been established on border areas.

[Surveillance on poliomyelitis neutralization antibody level in the border areas in Jilin province]

OBJECTIVE

This project is designed for understand poliomyelitis (Polio) neutralization antibody level in the the border areas in Jilin province.

METHOD

263 serum samples were collected from age groups of under 1-year-old, 1-2, 3-4, 5-6, 7-14, 15-19 and above 20-years-old. Microplate neutralization test was used to determine antibody level.

RESULT

Positive rates of neutralization antibody against Polio type I, II, III were 94.98%, 94.59%, 92.28%. The geometric mean titre of Polio type I, II, III were 1:40.53, 1:29.68, 1:20.71 respectively,which was decreased with the age increasing.

CONCLUSION

The population especially the population under 15-years-old lived in places that near the border in Jilin province had good immunity barriar against poliomyelitis.

[Analysis of polio antibody levels in healthy population in Beijing in 2007]

OBJECTIVE

To investigate the poliomyelitis antibody level in healthy people in Beijing.

METHODS

10 age groups (0, 1 to 4, 5 to 9, 10 to 14, 15 to 19, 20 to 24, 25 to 29, 30 to 34, 35 to 39, and > or = 40) were sampled by the Multi-stage stratified sampling method in 7 districts in Beijing, and 1552 sera from healthy population were collected. The poliomyelitis antibody was determined with microcell neutralization method.

RESULTS

The neutralized antibody-positive rate for polio I, II, III were 97.04%, 97.29% and 91.04% respectively, the geometric mean titers (GMT) were 1:70.05, 1:54.60, and 1:31.83 respectively. A trend of decreasing was observed in the GMTs with increasing age and years after immunization. There were no significant differences in antibody levels between different gender, residents or regions. The results of multiple-factors analysis showed that the GMTs were significantly associated with age and the years after immunization.

CONCLUSION

A stable immunization barrier has been established in healthy population in Beijing.

[Paralytic poliomyelitis in Russian Federation in 1998-2005]

From 1998 through 2005 3,294 cases of acute flaccid paralysis (AFP) including 93 cases with clinical picture of poliomyelitis were registered in Russian Federation. From the latter cases 91 were classified as vaccine-associated paralytic poliomyelitis (VAPP): 66 were VAPP cases in oral poliomyelitis vaccine (OPV) recipients and 25--VAPP cases in contacts. VAPP rate was 1 case per 1.6 million of distributed OPV doses, 1 case per 2.2 million doses for OPV recipients, and 1 case per 186,000 doses for recipients of 1st OPV dose in children aged < 1 year. Majority of VAPP cases in recipients occurred after 1st dose (89.4%) and in contacts--in non-vaccinated children (76%). Mean interval between OPV administration and onset of VAPP in recipients was 21 days. Children aged < 1 year were predominant among VAPP cases (92.4% among recipient VAPP cases, and 80% among contact VAPP cases). Majority of the patients had unfavorable health status including defects of immunity. Most of poliovirus strains isolated from VAPP cases belonged to type 3 (52.9%) whereas to type 2 and 1--29.8% and 17.4% of strains respectively. All VAPP cases were associated with vaccine-derived polioviruses. A highly diverged poliovirus type 1 (2.65% of nucleotide substitutions in VP1 region) was isolated from patient with contact VAPP. Formation of poliovirus-neutralizing serum antibodies in children with VAPP including persons with immunodeficiency reflects the ability of the organism to produce specific antiviral immune response.

[Collective poliomyelitis immunity in the adult population and its impact on eradication of this infection]

Collective poliomyelitis immunity was studied in 6339 donors from 19 towns and cities of Russia. Its stress substantially varied in different towns and cities. Studies of strain-specific antibodies to vaccine and wild viruses of poliomyelitis in donors from 4 towns established that the immune persons were more in the town where wild polioviruses had previously circulated than in those where the circulation of wild polioviruses had been limited and immunity resulted from vaccination. Circulation of vaccine viruses and reversion of their neurovirulent properties should be expected in the town where there are low collective poliomyelitis immunity rates. It is concluded that it is impossible to eradicate poliomyelitis as infection today; it is possible only to eliminate the disease if further vaccination of children is performed with live poliomyelitis vaccine.

1,25-dihydroxyvitamin d3 enhances systemic and mucosal immune responses to inactivated poliovirus vaccine in mice

1,25-Dihydroxyvitamin D3 (DHVD3) coadministered with monovalent inactivated poliovirus vaccine (IPV) of all 3 serotypes significantly enhances antipoliovirus systemic and mucosal immunity in mice. Although serum immunoglobulin G antibodies are significantly higher in serotypes 2 and 3, and although salivary immunoglobulin A is significantly increased in serotypes 1 and 3, DHVD3 had the most dramatic effect on the level of neutralizing serum antibodies of all 3 IPV serotypes. These findings suggest a possible use of vitamin D3 as an adjuvant for currently used and proposed new Sabin IPVs.

Circulating leukocyte and cytokine responses to measles and poliovirus vaccination in children after ultraviolet radiation exposures

Suberythemal ultraviolet radiation (UVR) exposures of children are used routinely in Russia to prevent rickets and to strengthen general health. The aim of the present study was to re-evaluate the effects of such a regime on immune responses as UVR is now recognised to suppress cell-mediated immunity in many animal models. Seventeen infants were immunised with attenuated measles and recall polio vaccines of whom 10 had been given a course of prophylactic UV exposures before the vaccinations. All the infants in the study developed an acute infectious conjunctivitis one week prior to the vaccinations and were convalescent at the time of the vaccination. They were bled on the day of the vaccinations and at several times thereafter to assess leukocyte percentages and plasma cytokine levels. On the day of the vaccinations, an active immune response was apparent. The UV-exposed children differed from the unexposed children by having a smaller percentage of natural killer cells and a higher percentage of CD25-positive cells. In the days following the vaccinations, the UV-exposed infants had a lowered percentage of total lymphocytes with increased percentages of monocytes, eosinophils, neutrophils and HLA-DR-positive cells as well as higher concentrations of plasma IL-1beta and IL-10 compared with the unexposed infants. There were no local or systemic clinical reactions to the vaccines in the UV-group while a moderate rise in temperature of three children in the unexposed group occurred. Thus the UV irradiations modulated leukocyte percentages and plasma cytokine levels following the vaccinations, perhaps through the activation of a T helper 2-like response.

[Lipid peroxidation in neurological pathology in children]

The intensity of lipid peroxidation (LPO) was studied by the content of the listed below in erythrocytes of children with neurological pathology: diene conjugates, trienketones and LPO products. Intensified LPO processes were registered in children with neurology and primarily in those with cerebral spastic infantile paralysis (CSIP). The detected changes in the LPO products of erythrocyte membranes depended on a disease variation on an intellectual development of sick child. The LPO activation affects possibly the development (lesion) of craniocerebral innervation in patients. Changed LPO parameters were found in examined sick children to be most closely related with the development of their motor skills and with the formation of the bone-muscle system, thus, an essentially higher content of LPO products was registered in erythrocytes of children with a reduced muscular activity (in those not capable of sitting, standing or walking). Considering the above stated and with respect to the deficit of Vitamin E registered in such patients, children with CSIP or with impending CSIP need, obviously a prolonged membrane-stabilizing therapy by antioxidants and essential phospholipids including traps of radicals, which should cut the number of children with severe CSIP and with residual perinatal lesions of the central nervous system.

Hormone replacement therapy and health behavior in postmenopausal polio survivors

OBJECTIVES

Little is known about menopause and hormone replacement therapy (HRT) use in women with disabilities. The objectives of this study were to explore the health behaviors, health outcomes, and efficacy of HRT in a group of postmenopausal polio survivors and to compare selected outcomes to nationally representative cohorts.

METHODS

One hundred and thirty-one postmenopausal polio survivors completed self-report surveys on health behaviors, HRT use, functional status, and psychosocial well-being. During a physical examination, fasting cholesterol and body mass index (BMI) were collected. Independent sample t-tests and Chi-square analysis were used to compare HRT users and non-users on health behaviors and health outcomes; logistic regression was used to predict HRT use.

RESULTS

Prevalence of HRT use was 58%. Only BMI predicted HRT use (OR = 0.30, CI: 0.11-0.81). HRT users had better high density lipoprotein (HDL), low density lipoprotein, total cholesterol/HDL ratios, lower BMIs, were more confident when communicating with their physicians, more likely to discuss menopause with their physician, and experienced greater overall stress. HRT was not associated with health behavior, health-related quality of life, mood, or life satisfaction. Compared to non-disabled women, more of these women had higher total cholesterol, obesity, more sleeping problems, and were less likely to vigorously exercise or smoke.

CONCLUSIONS

HRT did not confer substantial benefits in these postmenopausal polio survivors to warrant them using HRT at a higher rate than their non-disabled peers. Comparisons to their non-disabled peers suggested they may be at higher risk for adverse health problems associated with postmenopause.

[Immunoprophylaxis of poliomyelitis in Ukraine with the use of inactivated vaccine]

In connection with the cessation of the circulation of "wild" poliovirus on the territory of the European region, including Ukraine, the strategy of the vaccinal prophylaxis of poliomyelitis is reviewed. Its main aims are the creation of a high level of the specific protection of the population, the prophylaxis of vaccine-associated paralytic poliomyelitis and a decrease in the intensity of the circulation vaccine polioviruses. These aims may be achieved only by the inclusion of vaccinations with inactivated poliomyelitis vaccine (IPV) into the immunization schedule. IPV "Imovax Polio" produced by the firm "Aventis Pasteur" (France) has been shown to have low reactogenicity and high effectiveness, especially with respect to type 3 poliovirus, under the conditions of Ukraine. On the basis of our studies all children, starting from the age of 3 months, are recommended to be vaccinated first with two injections of IPV, followed by further immunization with oral vaccine.

Evaluation of Immunogenicity and Protective Properties of Inactivated Poliovirus Vaccines: A New Surrogate Method for Predicting Vaccine Efficacy

An assay for the evaluation of protective properties of inactivated poliovirus vaccines (IPVs) in transgenic (Tg) mice susceptible to poliovirus has been developed and optimized for type 2 IPV. This method was used to compare the immunogenicity and protective properties of experimental IPV produced from the attenuated Sabin strain (sIPV) with those of conventional IPV (cIPV) produced from the wild-type (wt) poliovirus MEF-1 strain. Modified enzyme-linked immunosorbent assays (ELISAs) were used to measure immune response in serum and saliva samples from test mice. Tg mice were vaccinated and were challenged either with wt poliovirus or virulent poliovirus derived from the vaccine strain. Compared with cIPV, sIPV induced lower levels of antibodies and did not completely protect mice against challenge with wt virus but did protect mice against challenge with the virulent vaccine-derived strain. This may be due to an 18% nucleotide difference between the MEF-1 and Sabin 2 strains, resulting in 72 amino acid substitutions and leading to antigenic dissimilarity. Immunological properties of both strains, revealed by cross-neutralization tests and ELISAs, confirmed that MEF-1 possesses broader immunogenicity than does Sabin 2. This animal model may be used for the assessment of new IPVs and of combination vaccines containing an IPV component.

[Strain-specific antibodies as an indicator of the circulation of wild poliomyelitis viruses and their role in the formation of collective immunity in the population]

Essential differences in the intensity of collective immunity to poliomyelitis in the donors of Moscow and Kaluga were established. To find out the nature of high characteristics of collective immunity to poliovirus, types 1 and 2, in the donors of Kaluga, strain-specific antibodies to wild and vaccine polioviruses were studied. In a considerable number of donors strain-specific antibodies to poliovirus, types 1 and 2, were detected. This made it possible to presume a sufficiently wide circulation of these viruses among the population of the city in the middle of the 20th century and, as a consequence, high level of collective immunity appeared. Strain-specific antibodies to poliovirus of type 3 were rarely detected. This made it possible to suggest that the circulation of viruses of this type among the population was limited. Immunity to viruses of this type was due only to immunization. For this reason the characteristics of collective immunity in the donors of Moscow and Kaluga coincided. The detection of strain-specific antibodies to poliomyelitis virus allowed to retrospectively form the opinion of the spread and time of the circulation of wild poliomyelitis viruses in the population.

A poliomyelitis model through mucosal infection in transgenic mice bearing human poliovirus receptor, TgPVR21

Transgenic mice bearing the human poliovirus receptor (TgPVR) are less susceptible to oral inoculation, although they are susceptible to parenteral inoculation. We investigated the susceptibility of TgPVR 21 line [Arch. Virol. 130 (1994) 351] to poliovirus through various mucosal routes. Intranasal inoculation of a neurovirulent Mahoney strain (OM1) caused flaccid paralysis with viral replication in the central nervous system at a dose of 10(6) cell culture infectious dose (CCID50), in contrast, no paralysis following oral or intragastric inoculation of the same dose. Intranasal inoculation of a vaccine strain, Sabin 1, at 10(6) CCID50, resulted in no paralysis. Initial replication of poliovirus in the nasal cavity was confirmed by virus isolation and detection of negative-stranded replicative intermediates by RT-PCR and viral antigens using a high-sensitive immunohistochemistry and genome/transcripts by in situ hybridization. Poliovirus-specific IgG antibodies were elevated in the sera of surviving TgPVR21. This model can be used as a mucosal infection model and for differentiation of neurovirulent and attenuated poliovirus strains.

2001 serological survey in the Czech Republic--poliomyelitis

Regular vaccination against poliomyelitis was started in 1960 with oral polio vaccine (OPV). Since 1992 a trivalent OPV has been administered in five doses within a nationwide vaccination campaign. The immunization coverage varies between 96.8% and 98.2% after 4 OPV doses, reaching 98.0% to 98.9% after the fifth dose. No case of indigenous poliomyelitis has been reported in the Czech Republic since the second half of 1960. In 2001, 3,230 sera were tested for the presence of antibodies against poliovirus of types 1, 2 and 3 using a virus neutralization microassay. The prevalence rates of antibodies vary between 96.0% and 100% for types 1 and 2 and between 95.1% and 100% for type 3, with the exception of the highest age group, in which the prevalence rates of antibodies against poliovirus of all three types are 92.2%.

GM1 antibodies in post-polio syndrome and previous paralytic polio

We studied the relationship between post-polio syndrome (PPS) and GM1 antibodies, since such antibodies have been associated with PPS and motor neuron disorders. Sera from 144 patients with previous poliomyelitis (105 paralytic, 22 nonparalytic and 17 PPS), 60 with previous Guillain-Barré syndrome, 44 with amyotrophic lateral sclerosis (ALS) and 22 healthy blood donors were analyzed with ELISA for GM1 IgM, IgG and IgA antibodies. GM1 antibodies were present in 14% of the PPS patients, but the prevalence did not differ significantly from that of the other groups. Our study does not support the hypothesis that GM1 antibodies are involved in the pathogenesis of PPS.

Poliovirus pathogenesis in a new poliovirus receptor transgenic mouse model: age-dependent paralysis and a mucosal route of infection

We constructed a poliovirus receptor (PVR) transgenic mouse line carrying a PVR delta cDNA driven by a beta-actin promoter. We refer to this model as the cPVR mouse. The cPVR mice express Pvr in a variety of tissues (including small intestines, brain, spinal cord, muscle, blood and liver) and are susceptible to infection after intraperitoneal, intracerebral or intramuscular inoculation of poliovirus. After intraperitoneal inoculation, poliovirus replication is observed in cPVR muscle, brain, spinal cord and, notably, small intestine. The cPVR mice exhibit a striking age-dependent paralysis after intramuscular infection, with 2-week-old mice being 10,000-fold more susceptible to paralytic disease than adult mice. The cPVR mice are also susceptible to paralysis following intranasal infection with poliovirus. After intranasal infection, virus replication is observed in the olfactory bulb, cerebrum, brain stem and spinal cord, suggesting that intranasal infection of cPVR mice is a model for bulbar paralysis. Intranasally infected mice frequently display unusual neurological behaviours. The PVR transgenic mouse reported here provides the first available model for a mucosal route of infection with poliovirus.

Immunoglobulin a as a serological marker for the (silent) circulation of poliovirus in an inactivated poliovirus-vaccinated population

Poliovirus-specific immunoglobulin A (IgA) is detected after infection with wild-type virus or vaccination with live attenuated oral poliovirus (OPV) but not after vaccination with inactivated poliovirus (IPV). We examined whether the presence of IgA in serum can be used as a marker for poliovirus circulation in IPV-vaccinated populations in The Netherlands. In seronegative persons challenged with OPV, the sensitivity of this marker was 76%-86%. Results from a serosurvey showed a high seroprevalence (63%-73%) of IgA in the population born before vaccination was introduced in The Netherlands, which reflects natural exposure. The start of the vaccination program in 1957 corresponded to a reduction in the IgA seroprevalence in both vaccinated (2.1%-4.5%) and nonvaccinated groups (8.3%-11.7%). The presence of IgA-positive persons in the population could largely be explained by the occurrence of episodes of proven poliovirus circulation. We propose to use the detection of poliovirus-specific IgA as a tool to monitor virus circulation in IPV-vaccinated and nonvaccinated populations, to aid the poliovirus eradication process.

[Introduction to a study of specific antibodies (IgG and IgM) detection with ELISA in the diagnosis of poliomyelitis]

Samples of single sera collected from 38 patients with different clinical diagnosis were studied in order to perform ELISA techniques with the purpose of detecting poliomyelitis IgG and IgM antibodies. The résults were compared through antibody titration by neutralization test. 21 pairs of sera from infants suffering from acute flaccid paralysis were studied by ELISA-IgM, ELISA-IgG and neutralization test. Stool samples were collected from 20 of the latter patient. Wild poliovirus type 1 was isolated in 8 cases. ELISA-IgM technique was positive in 14 cases. The true positive poliomyelitis diagnosis was based on the persistence of flaccid paralysis 60 days after the onset and on wild poliovirus isolation with significant increase in antibody level. 16 cases were classified as poliomyelitis, 2 cases as non poliomyelitic paralysis and 3 cases as undetermined. 16 out of the 18 well established diagnosis were in agreement (88.8%) with the detection or not of IgM antibodies by ELISA. The specificity of these IgM ELISA antibodies was examined by studying 11 cases of lymphocytic meningitis. Cross reaction in serological responses between polioviruses and coxsackieviruses was observed. These cross reactions should be evaluated by studying a greater number of cases. The poliovirus ELISA-IgM is a sensitive, economical and rapid method to be used in poliomyelitis diagnosis to complete the neutralizing test and virus isolation.

Age- and dose-interval-dependent antibody responses to inactivated poliovirus vaccine

Antibody responses were studied in five groups of children immunized with different three-dose schedules of inactivated poliovirus vaccine (IPV). The age of the child at the first dose (1-4 months) and the interval between the first and second doses (2-4 months) influenced the initial responses in a serotype-dependent manner. All the groups attained sufficient antibody level after three doses but the third dose given at 18 months resulted in higher persisting antibody levels than that given at 12 months. The highest persisting antibody titers against PV1 and PV2 (but not against PV3) at the age of 3 years were measured in the control group immunized with the current schedule (P < 0.001) in which the first dose is given at 6 months. The level of maternal antibodies present at the time of the first dose correlated negatively with the antibody titers as late as at 3 years of age. It is concluded that three doses of IPV given in widely variable schedules may result in satisfactory immune responses in children but, for optimal results, very early onset of the program and short dosage intervals should be avoided.

Problems with biotin-labelled virions as probes in poliovirus-specific mu-capture-IgM assays

BACKGROUND

We have previously developed a mu-capture-based radioimmunoassay (RIA) for detecting virus-specific IgM for the diagnosis of poliomyelitis. To probe captured IgM we used radiolabelled, purified preparations of representatives of each poliovirus serotype (Roivainen M, Agboatwalla M, Stenvik M, Rysa T, Akram DS, Hovi T. J Clin Microbiol 1993;31:2427-32). However, this assay is not directly applicable for wider use because preparation and handling of radioactive reagents is cumbersome and potentially hazardous.

OBJECTIVES

To develop a non-radioactive modification of the assay retaining the number of steps and reagents to a minimum.

STUDY DESIGN

Replacement of radioactive labelling by in vitro biotinylation of purified virions, and detection of bound virions with horseradish peroxidase-conjugated streptavidin. To study sensitivity and poliovirus serotype-specificity, 129 sera and 115 CSF specimens from children with acute poliomyelitis were used in comparative tests with the in-house RIA. In addition, sera from 40 healthy adults and 11 paired sera from patients with non-polio enterovirus infection were used to assess specificity.

RESULTS

While results with the new test on specimens from clinically confirmed polio patients revealed some correlation with those obtained in the in-house RIA, studies on sera from healthy adults indicated, that non-specific binding of biotinylated virions is difficult to control. Moreover, examination of sera from patients with non-polio enterovirus infection suggested frequently occurring cross-reactivity between immune responses induced by polio- and other enterovirus infections. The latter were also seen in the RIA.

CONCLUSION

Cross-reactive epitopes between poliovirus serotypes and between polioviruses and other enteroviruses may compromise the use of an assay for virus-specific IgM for poliovirus diagnosis. Biotinylation of the virions seemed to aggravate these problems.

The effect of pentoxifylline (PTX) on Theiler's murine encephalomyelitis (TMEV)-induced demyelinating disease

Pentoxifylline (PTX) has been recently shown to have a variety of immunomodulatory effects. PTX suppresses the production of tumor necrosis factor-alpha (TNF-alpha) and T helper type 1 (Th1) cytokine, interferon-gamma (IFN-gamma), whereas it increases the production of Th2 cytokines, such as interleukin-4 (IL-4) and IL-10. In the pathogenesis of Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease (TMEV-IDD), encephalitogenic Th1 cells may play a major role. We examined the effect of PTX treatment on TMEV-IDD. We treated SJL/J mice, inoculated TMEV intracerebrally, with either PTX or saline from days -2 to 12 and days 14 to 27 postintracerebral infection. In the group of mice treated with PTX from days -2 to 12, the onset of TMEV-IDD was suppressed. On the other hand, in the group of mice treated with PTX from days 14 to 27 or saline, the onset of TMEV-IDD was not inhibited. The results of enzyme-linked immunospot (ELISPOT) assay of spleen cells of mice showed that the production of TNF-alpha and IFN-gamma was significantly inhibited (TNF-alpha and IFN-gamma, p < 0.001) and IL-4 and IL-10 production was significantly increased (IL-4, P < 0.001; and IL-10, P < 0.05, respectively) in the group of mice treated with PTX from days -2 to 12. These findings suggest that PTX suppresses the onset of TMEV-IDD by suppressing the production of TNF-alpha and modulating Th1-dominant immune responses into Th2-dominant ones.

A population-based seroprevalence study in South Africa as a tool in the polio eradication initiative

A seroprevalence study for poliomyelitis was carried out on a sample of sera from a serum bank used for a vitamin A study. Vaccination coverage was satisfactory (80% or more) in five of nine provinces, although a prevalence of antibody to polio of 80% or more was found in all provinces. Serologic immunity (i.e., the prevalence of neutralizing antibodies) exceeded vaccination coverage, suggesting secondary spread of vaccine virus. However, whether or not water was supplied through a piped system was not associated with secondary spread of vaccine virus to nonvaccinated children. Seroprevalence studies are a valuable adjunct to acute flaccid paralysis surveillance, which is the standard surveillance instrument for the poliomyelitis eradication initiative. The use of available and suitable serum banks for seroprevalence investigations is a relatively cheap monitoring option that can yield very valuable information for the eradication initiative.

Evaluation of a poliovirus-binding inhibition assay as an alternative to the virus neutralization test

An enzyme-linked immunosorbent assay (ELISA)-based poliovirus-binding inhibition (PoBI) test to detect and quantify antibodies to polioviruses was optimized and evaluated for use in population studies as an alternative to the virus neutralization test (NT) in tissue culture. The sensitivities of the inhibition ELISA compared with the NT in an inactivated poliovirus vaccine (IPV)-vaccinated population were 98.6, 97.4, and 92.1% for serotypes 1, 2, and 3, respectively. The specificities of the PoBI test, as determined with sera from nonvaccinated persons, were also high for all three serotypes (99.0, 95.8, and 100%, respectively). Antibodies to other enteroviruses did not cross-react in the serotype 1 and 3 PoBI, and only levels of cross-reactivity were found for serotype 2. We found high correlations between the PoBI and NT titers for serotypes 1 and 2 in IPV-vaccinated blood donors (0.97 and 0.95), in oral poliovirus vaccine (OPV)-vaccinated blood donors (0.91 and 0.95), and in naturally immune persons (0.90 and 0.87). The correlation coefficient for serotype 3, however, was significantly lower in OPV-vaccinated blood donors (0.73) and in naturally immune persons (0.76) than in IPV-vaccinated persons (0.94; P < 0.01). These results indicate that the antibody response to serotype 3 poliovirus in IPV recipients is different from that in OPV recipients and naturally infected persons. We conclude that the PoBI test is a suitable alternative to the NT for estimating the seroprevalence of neutralizing antibodies to poliovirus, especially in large-scale population studies.

A serological indication of the existence of a guineapig poliovirus

Attempts were made to clarify whether laboratory guineapigs may harbour a poliovirus which, in 1911, was described as the cause of a disease called guineapig lameness. By the use of ELISA for antibodies against the poliovirus, Theiler's murine encephalomyelitis virus (TMEV), it was shown that two pet shop guineapigs suffering from lameness had extremely high titres against poliovirus, while healthy guineapigs from the same pet shop were negative. Clearly positive results were also found in 35 out of 152 laboratory guineapig sera. Positive results were found in only two out of six breeding centres, but in three out of three experimental units, all of which purchased guineapigs from one of the seropositive breeding colonies. The diseased guineapigs recovered fully after treatment with vitamins in the drinking water, a treatment used for guineapig lameness by small animal practitioners. A theory that vitamin C deficient guineapigs are, due to an impaired steroid secretion, predisposed to succumbing to infection and develop demyelinating disease similar to that in TMEV infected mice is discussed briefly. Guineapig sera were also tested serologically for other infections. Antibodies against lymphocytic choriomeningitis virus, Clostridium piliforme and Toxoplasma gondii were not found, but one breeding colony was infected with adenovirus, pneumonia virus of mice, reovirus type 3, Sendai virus, parainfluenza (simian) virus type 5 and Encephalitozoon cuniculi. Two other breeding colonies were infected with both reovirus type 3 and E. cuniculi. In all three experimental units infection with adenovirus was observed, and in two of these Sendai virus and E. cuniculi antibodies were also found. The pet shop guineapigs were infected with adenovirus, reovirus type 3 and E. cuniculi.

Combined immunization of infants with oral and inactivated poliovirus vaccines: results of a randomized trial in The Gambia, Oman, and Thailand. WHO Collaborative Study Group on Oral and Inactivated Poliovirus Vaccines

To assess an immunization schedule combining oral (OPV) and inactivated poliovirus vaccines (IPV), a clinical trial was conducted in The Gambia, Oman, and Thailand. Children were randomized to receive OPV at birth and at 6, 10, and 14 weeks of age; OPV at birth followed by both OPV and IPV at 6, 10, and 14 weeks of age; or placebo at birth followed by IPV at 6, 10, and 14 weeks of age. Serum specimens were available at 24 weeks for 1291 (77%) of 1685 enrolled infants. In the combined-schedule group, the proportion of children seropositive at 24 weeks was 95%-99% for type 1, 99%- 100% for type 2, and 97%-100% for type 3. In The Gambia and Oman, the combined schedule performed significantly better than OPV for type 1 (95%-97% vs. 88%-90%) and type 3 (97%-99% vs. 72%-73%). Across the study sites, IPV given at 6, 10, and 14 weeks of age provided inadequate protection against poliovirus. The combined schedule provided the highest levels of serum antibody response, with mucosal immunity equivalent to that produced by OPV alone.

Immunity status to poliovirus in Veneto region (north-east Italy). A seroepidemiological survey

The immunity state to poliovirus types 1, 2, and 3 of a population aged 2 to 75 years was determined by examining 274 sera collected in the Venice mainland (North-East Italy). Altogether, the neutralizing antibody prevalences (at a titre > or = 1:2) for poliovirus 1, 2, and 3 were 99.0 percent (geometrical mean titres [GMT]: 72.1), 99.6 percent (GMT: 95.9) and 98.2 percent (GMT: 17.3), respectively, and all the age groups also showed very good levels of humoral immunity. High antibody titres (> or = 1:256) to one or more types of poliovirus were demonstrated in older age groups also, possibly indicating exposure to natural polioviruses or contact with vaccine strains. Although probably all the older subjects had practically acquired their antibodies as a result of natural infection and those under 30 through vaccination, these results indicate that the humoral immunity against poliomyelitis in our population is satisfactory, and the maintenance of such good protection level depends on an effective immunization program.

[Serologic marker as indicator of no circulation of poliovirus in Cuba]

The surveillance of the circulation of the wild poliovirus is an essential element for the eradication of poliomyelitis. The Pan-American Health Organization emphasises on the etiological study of acute flaccid paralysis in order to achieve this aim. The characteristics of our program against this entity allowed to use the presence of antibodies in a sample obtained in February from the infant population born on July during the previous year as criteria to know the circulation of wild poliovirus. In 727 infants studies in the country (5% of the total number of births during July), 99.1% showed no antibodies with a titre equal or greater than 1:10. Low titres found in 7 infants were considered as a remnant from maternal transmission. Results obtained represent a strong evidence of the fact that there is no environmental circulation of poliovirus during the period which had the greatest incidence of the disease.

Serum antibodies to polioviruses in a Tuscan population, Italy

In order to study the serological status of a population against poliomyelitis, neutralizing antibody for the three types of polioviruses were examined in 742 serum specimens from individuals aged from 1 to 70 years and over were collected during 1985. Sixty-two percent of the sera had antibodies (titre greater than or equal to 1:8) to all three polioviruses, while 5% had no poliovirus antibody at all. However the rates of seropositivity did vary with age: the 10-19 age group had the lowest frequency of antibody (38%) to the three viruses and the difference between the percentage of this group and the previous (1-10 years) and following ones (20-70 years and over) was highly significant. The results of this seroprevalence survey indicate a gap in immunity to poliomyelitis in the population examined.

Plasma lipid and lipoprotein concentrations in symptomatic postpolio patients

This study reports lipid and lipoprotein concentrations in postpolio patients seen in our postpolio clinic who were evaluated for complaints of progressive weakness, fatigue, and/or pain. Concentrations of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) were determined after an overnight fast. Sixty-four patients (24 men and 40 women) with a mean age of 48 +/- 10 years were studied. Mean (+/- SD) lipid concentrations (mg/dL) for men and women, respectively, were 220 +/- 46 and 213 +/- 43 for TC; 38.5 +/- 8.6 and 59.1 +/- 18.1 for HDL-C; 148 +/- 46 and 129 +/- 36 for LDL-C; and 205 +/- 107 and 105 +/- 55 for TG. Hyperlipidemia was found in 16 of 24 men and 10 of 40 women. In the men, mean HDL-C concentration was in the lowest decile of our hospital laboratory's reference range, whereas mean TC/HDL-C ratio was elevated above the recommended value. It is suggested that lipid and lipoprotein concentrations be evaluated in postpolio patients because a high prevalence of lipid/lipoprotein disorders was found in our subjects. Further research is needed on this topic.

Isoelectric focusing studies of serum and cerebrospinal fluid in patients with antecedent poliomyelitis

The post-poliomyelitis syndrome (PPS) refers to symptoms of new weakness, fatigue, and pain years after recovery from acute poliomyelitis. Oligoclonal IgG bands have been reported in the cerebrospinal fluid (CSF) from PPS patients, suggesting that the syndrome is immune mediated or caused by persistent viral infection. We studied 15 paired serum and CSF samples and 6 unpaired CSF samples from a total of 21 patients with a prior history of poliomyelitis. Quantitative immune studies failed to show evidence for increased intrathecal IgG production relative to patients with noninflammatory central nervous system (CNS) disease. We found definite oligoclonal IgG bands in the CSF from only 1 patient, who also carried a diagnosis of multiple sclerosis. An isoelectric focusing poliovirus antigen overlay study showed evidence that suggested a CNS-specific antipoliovirus immune response in only 1 patient. Our results fail to support a dysimmune or persistent viral cause for post-poliomyelitis progressive muscular atrophy or PPS.

Serum creatine kinase in the post-polio population

Elevated creatine kinase (CK) levels may be noted in neuromuscular patients as a result of muscle damage and necrosis. We measured the serum CK levels of 62 post-polio patients with chronic neurologic disease (Neuro) and 13 post-polio patients with no evidence of neurologic compromise (Control). Patient groups were comparable for age, gender and years since onset of poliomyelitis. The Neuro group had substantially increased CK levels compared with the Control group, 211 +/- 19.0 IU v 114 +/- 26.2 IU (mean +/- 1 SE; P less than 0.05). Of the Neuro group, 40% had abnormally elevated CK values, compared with 8% of the Control group. Within the Neuro group, there was a robust correlation between elevated CK values and self-reports of strenuous work and level of community ambulation (P less than 0.05). These findings support the hypothesis that chronic muscle overuse may be a contributing factor to the advanced senescence reported by post-polio patients with neuromuscular compromise.

Chromosome aberrations in lymphoid tissues of different origin and immune responsiveness of Macaca rhesus monkeys infected with poliovirus type 1

A virulent strain of poliovirus type 1 induced aberrations in the chromosomal apparatus of both blood lymphocytes and bone marrow cells in infected Macaca rhesus monkeys. In addition, there were significant differences in the type and degree of aberrations, occurring in bone marrow cells and blood lymphocytes. Changes were also observed in the mitotic activity of bone marrow cells. Poliovirus inhibited the lymphocyte blast transformation (LBT) to phytohaemagglutinin (PHA), but enhanced the LBT to virus-specific antigen and the reactivity of neutrophils.

Local antibody response to experimental poliovirus infection in the central nervous system of rhesus monkeys

By employing the techniques of immunofluorescence and radioimmunodiffusion using (32)P-labeled poliovirus as the antigen, the immunoglobulin response to poliovirus in serum, nasopharynx, spinal fluid, and in different segments of the central nervous system (CNS) was studied after intramuscular, oral, intranasal, and intrathalamic administration of inactivated (Salk), live attenuated (Sabin), or live virulent (Mahoney) type I poliovirus. Spinal fluid gammaG antibody was detected after immunization with Sabin or Mahoney virus and intramuscular administration of Salk vaccine. The response in the CNS was characterized by the appearance of gammaG antibody after oral or intrathalamic administration of Mahoney virus and rarely after intrathalamic inoculation of Sabin vaccine. The antibody activity in CNS was limited to the areas of poliovirus replication. Intrathalamic immunization with Mahoney virus resulted in local gammaG antibody production in the CNS in the absence of any detectable response in serum. Discrete foci of gammaG-containing cells were observed in those areas of CNS which contained poliovirus antibody. No immunoglobulin-containing cells or poliovirus antibody was seen in the CNS of monkeys immunized with intramuscularly or orally administered Sabin or Salk vaccine and in sham-immunized control monkeys. It is suggested that the CNS, when stimulated locally with a potent replicating viral antigen, may manifest a specific local antibody response, which is independent of the response in serum.