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To inform response strategies, we examined type 1 humoral and intestinal immunity induced by 1) one fractional inactivated poliovirus vaccine (fIPV) dose given with monovalent oral poliovirus vaccine (mOPV1), and 2) mOPV1 versus bivalent OPV (bOPV). We conducted a randomized, controlled, open-label trial in Dhaka, Bangladesh. Healthy infants aged 5 weeks were block randomized to one of four arms: mOPV1 at age 6–10–14 weeks/fIPV at 6 weeks (A); mOPV1 at 6–10–14 weeks/fIPV at 10 weeks (B); mOPV1 at 6–10–14 weeks (C); and bOPV at 6–10–14 weeks (D). Immune response at 10 weeks and cumulative response at 14 weeks was assessed among the modified intention-to-treat population, defined as seroconversion from seronegative (<1:8 titers) to seropositive (≥1:8) or a four-fold titer rise among seropositive participants sustained to age 18 weeks. We examined virus shedding after two doses of mOPV1 with and without fIPV, and after the first mOPV1 or bOPV dose. The trial is registered at ClinicalTrials.gov (NCT03722004). During 18 December 2018 – 23 November 2019, 1,192 infants were enrolled (arms A:301; B:295; C:298; D:298). Immune responses at 14 weeks did not differ after two mOPV1 doses alone (94% [95% CI: 91–97%]) versus two mOPV1 doses with fIPV at 6 weeks (96% [93–98%]) or 10 weeks (96% [93–98%]). Participants who received mOPV1 and fIPV at 10 weeks had significantly lower shedding (p < 0·001) one- and two-weeks later compared with mOPV1 alone. Response to one mOPV1 dose was significantly higher than one bOPV dose (79% versus 67%; p < 0·001) and shedding two-weeks later was significantly higher after mOPV1 (76% versus 56%; p < 0·001) indicating improved vaccine replication. Ninety-nine adverse events were reported, 29 serious including two deaths; none were attributed to study vaccines. Given with the second mOPV1 dose, fIPV improved intestinal immunity but not humoral immunity. One mOPV1 dose induced higher humoral and intestinal immunity than bOPV. U.S. Centers for Disease Control and Prevention. [ABSTRACT FROM AUTHOR]

Background. Polio eradication efforts have been hampered by low responses to trivalent oral poliovirus vaccine (tOPV) in some developing countries. Since stomach acidity may neutralize vaccine viruses, we assessed whether administration of a buffer solution could improve the immunogenicity of tOPV.Methods. Healthy infants 4–6 weeks old in Sylhet, Bangladesh, were randomized to receive tOPV with or without a sodium bicarbonate and sodium citrate buffer at age 6, 10, and 14 weeks. Levels of serum neutralizing antibodies for poliovirus types 1, 2, and 3 were measured before and after vaccination, at 6 and 18 weeks of age, respectively.Findings. Serologic response rates following 3 doses of tOPV for buffer recipients and control infants were 95% and 88% (P = .065), respectively, for type 1 poliovirus; 95% and 97% (P = .543), respectively, for type 2 poliovirus; and 90% and 89% (P = .79), respectively, for type 3 poliovirus.Conclusions. Administration of a buffer solution prior to vaccination was not associated with statistically significant increases in the immune response to tOPV; however, a marginal 7% increase (P = .065) in serologic response to poliovirus type 1 was observed.Clinical Trials Registration. NCT01579825. [ABSTRACT FROM PUBLISHER]

Background: Intradermal administration of fractional inactivated poliovirus vaccine (fIPV) is a dose-sparing alternative to the intramuscular full dose. We aimed to compare the immunogenicity of two fIPV doses versus one IPV dose for routine immunisation, and also assessed the immunogenicity of an fIPV booster dose for an outbreak response.Methods: We did an open-label, randomised, controlled, inequality, non-inferiority trial in two clinics in Dhaka, Bangladesh. Healthy infants were randomly assigned at 6 weeks to one of four groups: group A received IPV at age 14 weeks and IPV booster at age 22 weeks; group B received IPV at age 14 weeks and fIPV booster at age 22 weeks; group C received IPV at age 6 weeks and fIPV booster at age 22 weeks; and group D received fIPV at 6 weeks and 14 weeks and fIPV booster at age 22 weeks. IPV was administered by needle-syringe as an intramuscular full dose (0·5 mL), and fIPV was administered intradermally (0·1 mL of the IPV formulation was administered using the 0·1 mL HelmJect auto-disable syringe with a Helms intradermal adapter). Both IPV and fIPV were administered on the outer, upper right thigh of infants. The primary outcome was vaccine response to poliovirus types 1, 2, and 3 at age 22 weeks (routine immunisation) and age 26 weeks (outbreak response). Vaccine response was defined as seroconversion from seronegative (<1:8) at baseline to seropositive (≥1:8) or four-fold increase in reciprocal antibody titres adjusted for maternal antibody decay and was assessed in the modified intention-to-treat population (infants who received polio vaccines per group assignment and polio antibody titre results to serotypes 1, 2, and 3 at 6, 22, 23, and 26 weeks of age). The non-inferiority margin was 12·5%. This trial is registered with ClinicalTrials.gov, number NCT02847026.Findings: Between Sept 1, 2016 and May 2, 2017, 1076 participants were randomly assigned and included in the modified intention-to-treat analysis: 271 in Group A, 267 in group B, 268 in group C, and 270 in group D. Vaccine response at 22 weeks to two doses of fIPV (group D) was significantly higher (p<0·0001) than to one dose of IPV (groups A and B) for all three poliovirus serotypes: the type 1 response comprised 212 (79% [95% CI 73-83]) versus 305 (57% [53-61]) participants, the type 2 response comprised 173 (64% [58-70]) versus 249 (46% [42-51]) participants, and the type 3 response comprised 196 (73% [67-78]) versus 196 (36% [33-41]) participants. At 26 weeks, the fIPV booster was non-inferior to IPV (group B vs group A) for serotype 1 (-1·12% [90% CI -2·18 to -0·06]), serotype 2 (0·40%, [-2·22 to 1·42]), and serotype 3 (1·51% [-3·23 to -0·21]). Of 129 adverse events, 21 were classified as serious including one death; none were attributed to IPV or fIPV.Interpretation: fIPV appears to be an effective dose-sparing strategy for routine immunisation and outbreak responses.Funding: US Centers for Disease Control and Prevention. [ABSTRACT FROM AUTHOR]

Background: Monovalent type 2 oral poliovirus vaccine (mOPV2) and inactivated poliovirus vaccine (IPV) are used to respond to type 2 poliovirus outbreaks. We aimed to assess the effect of two mOPV2 doses on the type 2 immune response by varying the time interval between mOPV2 doses and IPV co-administration with mOPV2.Methods: We did a randomised, controlled, parallel, open-label, non-inferiority, inequality trial at two study clinics in Dhaka, Bangladesh. Healthy infants aged 6 weeks (42-48 days) at enrolment were randomly assigned (1:1:1:1) to receive two mOPV2 doses (each dose consisting of two drops [0·1 mL in total] of about 105 50% cell culture infectious dose of type 2 Sabin strain) at intervals of 1 week, 2 weeks, 4 weeks (standard or control group), or 4 weeks with IPV (0·5 mL of type 1 [Mahoney, 40 D-antigen units], type 2 [MEF-1, 8 D-antigen units], and type 3 [Saukett, 32 D-antigen units]) administered intramuscularly with the first mOPV2 dose. We used block randomisation, randomly selecting blocks of sizes four, eight, 12, or 16 stratified by study sites. We concealed randomisation assignment from staff managing participants in opaque, sequentially numbered, sealed envelopes. Parents and clinic staff were unmasked to assignment after the randomisation envelope was opened. Laboratory staff analysing sera were masked to assignment, but investigators analysing data and assessing outcomes were not. The primary outcome was type 2 immune response measured 4 weeks after mOPV2 administration. The primary modified intention-to-treat analysis included participants with testable serum samples before and after vaccination. A non-inferiority margin of 10% and p=0·05 (one-tailed) was used. This trial is registered at ClinicalTrials.gov, number NCT02643368, and is closed to accrual.Findings: Between Dec 7, 2015, and Jan 5, 2016, we randomly assigned 760 infants to receive two mOPV2 doses at intervals of 1 week (n=191), 2 weeks (n=191), 4 weeks (n=188), or 4 weeks plus IPV (n=190). Immune responses after two mOPV2 doses were observed in 161 (93%) of 173 infants with testable serum samples in the 1 week group, 169 (96%) of 177 in the 2 week group, and 176 (97%) of 181 in the 4 week group. 1 week and 2 week intervals between two mOPV2 doses were non-inferior to 4 week intervals because the lower bound of the absolute differences in the percentage of immune responses were greater than -10% (-4·2% [90% CI -7·9 to -0·4] in the 1 week group and -1·8% [-5·0 to 1·5] in the 2 week group vs the 4 week group). The immune response elicited by two mOPV2 doses 4 weeks apart was not different when IPV was added to the first dose (176 [97%] of 182 infants with IPV vs 176 [97%] of 181 without IPV; p=1·0). During the trial, two serious adverse events (pneumonia; one [1%] of 186 patients in the 1 week group and one [1%] of 182 in the 4 week group) and no deaths were reported; the adverse events were not attributed to the vaccines.Interpretation: Administration of mOPV2 at short intervals does not interfere with its immunogenicity. The addition of IPV to the first mOPV2 dose did not improve poliovirus type 2 immune response.Funding: US Centers for Disease Control and Prevention. [ABSTRACT FROM AUTHOR]

Summary Background The provision of several doses of monovalent type 1 oral poliovirus vaccine (mOPV1) and bivalent OPV1 and 3 (bOPV) vaccines through campaigns is essential to stop the circulation of remaining wild polioviruses. Our study aimed to assess the shortening of intervals between campaigns with bOPV and mOPV1 and to assess the immunogenicity of bOPV in routine immunisation schedules. Methods We did an open-label, non-inferiority, five-arm, randomised controlled trial in Bangladesh. We recruited healthy infants aged 6 weeks at 42 immunisation clinics and randomly assigned them (with blocks of 15, three per group) to receive a short three-dose schedule of bOPV (bOPV short) or mOPV1 (mOPV1 short) with the first dose given at age 6 weeks, the second at age 8 weeks, and the third at age 10 weeks; or to a standard three-dose schedule of bOPV (bOPV standard) or mOPV1 (mOPV1 standard) or trivalent OPV (tOPV standard) with the first dose given at age 6 weeks, the second at 10 weeks, and the third at age 14 weeks. The primary outcome was the proportion of infants with antibody seroconversion for type 1, type 2, and type 3 polioviruses. The primary, modified intention-to-treat analysis included all patients who had testable serum samples before and after receiving at least one OPV dose. We used a 10% margin to establish non-inferiority for bOPV groups versus mOPV1 groups in seroconversion for type 1 poliovirus, and for bOPV1 short versus bOPV1 standard for types 1 and 3. This trial is registered at ClinicalTrials.gov , number NCT01633216 , and is closed to new participants. Findings Between May 13, 2012, and Jan 21, 2013, we randomly assigned 1000 infants to our study groups. 927 completed all study visits and were included in the primary analysis. Seroconversion for type-1 poliovirus was recorded in 183 (98%, 95% CI 95–100) of 186 infants given bOPV short, 179 (97%, 94–99) of 184 given bOPV standard, 180 (96%, 92–98) of 188 given mOPV short, 178 (99%, 97–100) of 179 given mOPV1 standard, and 175 (92%, 87–96) of 190 given tOPV standard. Seroconversion for type 2 was noted in 16 infants (9%, 5–14) on bOPV short, 29 (16%, 11–22) on bOPV standard, 19 (10%, 7–15) on mOPV short, 33 (18%, 13–25) on mOPV1 standard, and 182 (96%, 92–98) on tOPV standard. Seroconversion for type 3 was noted in 175 infants (94%, 90–97) on bOPV short, 176 (96%, 92–98) on bOPV standard, 18 (10%, 6–15) on mOPV short, 25 (14%, 10–20) on mOPV1 standard, and 167 (88%, 83–92) on tOPV standard. The short schedules for mOPV1 and bOPV elicited a non-inferior antibody response compared with the bOPV standard schedule. 104 adverse events were reported in 100 infants during follow up. 36 of these events needed admission to hospital (32 were pneumonia, two were vomiting or feeding disorders, one was septicaemia, and one was diarrhoea with severe malnutrition). One of the infants admitted to hospital for pneumonia died 5 days after admission. No adverse event was attributed to the vaccines. Interpretation Our trial showed that three doses of mOPV1 or bOPV with a short schedule of 2 week intervals between doses induces an immune response similar to that obtained with the standard schedule of giving doses at 4 week intervals. These findings support the use of these vaccines in campaigns done at short intervals to rapidly increase population immunity against polioviruses to control outbreaks or prevent transmission in high-risk areas. Funding Centers for Disease Control and Prevention and UNICEF. [ABSTRACT FROM AUTHOR]

Background Surveillance for acute flaccid paralysis with laboratory confirmation has been a key strategy in the global polio eradication initiative, and the laboratory platform established for polio testing has been expanded in many countries to include surveillance for cases of febrile rash illness to identify measles and rubella cases. Vaccine-preventable disease surveillance is essential to detect outbreaks, define disease burden, guide vaccination strategies and assess immunization impact. Vaccines now exist to prevent Japanese encephalitis (JE) and some etiologies of bacterial meningitis. Methods We evaluated the feasibility of expanding polio–measles surveillance and laboratory networks to detect bacterial meningitis and JE, using surveillance for acute meningitis-encephalitis syndrome in Bangladesh and China and acute encephalitis syndrome in India. We developed nine syndromic surveillance performance indicators based on international surveillance guidelines and calculated scores using supervisory visit reports, annual reports, and case-based surveillance data. Results Scores, variable by country and targeted disease, were highest for the presence of national guidelines, sustainability, training, availability of JE laboratory resources, and effectiveness of using polio–measles networks for JE surveillance. Scores for effectiveness of building on polio–measles networks for bacterial meningitis surveillance and specimen referral were the lowest, because of differences in specimens and techniques. Conclusions Polio–measles surveillance and laboratory networks provided useful infrastructure for establishing syndromic surveillance and building capacity for JE diagnosis, but were less applicable for bacterial meningitis. Laboratory-supported surveillance for vaccine-preventable bacterial diseases will require substantial technical and financial support to enhance local diagnostic capacity. [ABSTRACT FROM AUTHOR]

The term synanthropic describes organisms that thrive in human-altered habitats. Where synanthropic nonhuman primates (NHP) share an ecological niche with humans, cross-species transmission of infectious agents can occur. In Bangladesh, synanthropic NHP are found in villages, densely populated cities, religious sites, and protected forest areas. NHP are also kept as performing monkeys and pets. To investigate possible transmission of enteric picornaviruses between humans and NHP, we collected fecal specimens from five NHP taxa at16 locations in Bangladesh during five field sessions, from January 2007 to June 2008. Specimens were screened using real-time PCR assays for the genera Enterovirus, Parechovirus, and Sapelovirus; PCR-positive samples were typed by VP1 sequencing. To compare picornavirus diversity between humans and NHP, the same assays were applied to 211 human stool specimens collected in Bangladesh in 2007 to 2008 for acute flaccid paralysis surveillance. Picornaviruses were detected in 78 of 677 (11.5%) NHP fecal samples. Twenty distinct human enterovirus (EV) serotypes, two bovine EV types, six human parechovirus serotypes, and one virus related to Ljungan virus were identified. Twenty-five additional enteroviruses and eight parechoviruses could not be typed. Comparison of the picornavirus serotypes detected in NHP specimens with those detected in human specimens revealed considerable overlap. Strikingly, no known simian enteroviruses were detected among these NHP populations. In conclusion, enteroviruses and parechoviruses may be transmitted between humans and synanthropic NHP in Bangladesh, but the directionality of transmission is unknown. These findings may have important implications for the health of both human and NHP populations. [ABSTRACT FROM AUTHOR]

In 2012, the Strategic Advisory Group of Experts on Immunization (SAGE) recommended introduction of at least one inactivated poliovirus vaccine (IPV) dose in essential immunization programs. We evaluated systemic humoral and intestinal mucosal immunity of a sequential IPV-bivalent oral poliovirus vaccine (bOPV) schedule compared with a co-administration IPV + bOPV schedule in an open-label, randomized, controlled, non-inferiority, inequality trial in Dhaka, Bangladesh. Healthy infants aged 6 weeks were randomized to either: (A) IPV and bOPV at 6 and bOPV at 10 and 14 weeks (IPV + bOPV-bOPV-bOPV); or (B) IPV at 6 and bOPV at 10 and 14 weeks (IPV-bOPV-bOPV). Of 456 participants enrolled and randomly assigned during May-August 2015, 428 (94%) were included in the modified intention-to-treat analysis (arm A: 211, arm B: 217). Humoral immune responses did not differ at 18 weeks between study arms: type 1 (98% versus 96%; p = 0.42), type 2 (37% versus 39%; p = 0.77), and type 3 (97% versus 93%; p = 0.07). Virus shedding one week after the bOPV challenge dose in arm B was non-inferior to arm A (type 1 difference = -3% [90% confidence interval: -6 - 0.4%]; type 3 difference: -3% [-6 to -0.2%]). Twenty-six adverse events including seven serious adverse events were reported among 25 participants including one death; none were attributed to study vaccines. An IPV-bOPV-bOPV sequential schedule induced comparable systemic humoral immunity to all poliovirus types and types 1 and 3 intestinal mucosal immunity as an IPV + bOPV-bOPV-bOPV co-administration schedule., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Khalequ Zaman, Asma Binte Aziz, Mohammad Yunus, Warda Haque b reports financial support was provided by Centers for Disease Control and Prevention. Cynthia J Snider’s spouse previously owned stock in Sanofi Pasteur, (Published by Elsevier Ltd.)

In May 2016, the Global Polio Eradication Initiative (GPEI) coordinated the cessation of all use of type 2 oral poliovirus vaccine (OPV2), except for emergency outbreak response. Since then, paralytic polio cases caused by type 2 vaccine-derived polioviruses now exceed 3,000 cases reported by 39 countries. In 2022 (as of April 25, 2023), 20 countries reported detection of cases and nine other countries reported environmental surveillance detection, but no reported cases. Recent development of a genetically modified novel type 2 OPV (nOPV2) may help curb the generation of neurovirulent vaccine-derived strains; its use since 2021 under Emergency Use Listing is limited to outbreak response activities. Prior modeling studies showed that the expected trajectory for global type 2 viruses does not appear headed toward eradication, even with the best possible properties of nOPV2 assuming current outbreak response performance. Continued persistence of type 2 poliovirus transmission exposes the world to the risks of potentially high-consequence events such as the importation of virus into high-transmission areas of India or Bangladesh. Building on prior polio endgame modeling and assuming current national and GPEI outbreak response performance, we show no probability of successfully eradicating type 2 polioviruses in the near term regardless of vaccine choice. We also demonstrate the possible worst-case scenarios could result in rapid expansion of paralytic cases and preclude the goal of permanently ending all cases of poliomyelitis in the foreseeable future. Avoiding such catastrophic scenarios will depend on the development of strategies that raise population immunity to type 2 polioviruses., (© 2023 Society for Risk Analysis.)

Background: Novel oral poliovirus vaccine type 2 (nOPV2) was developed by modifying the Sabin strain to increase genetic stability and reduce risk of seeding new circulating vaccine-derived poliovirus type 2 outbreaks. Bivalent oral poliovirus vaccine (bOPV; containing Sabin types 1 and 3) is the vaccine of choice for type 1 and type 3 outbreak responses. We aimed to assess immunological interference between nOPV2 and bOPV when administered concomitantly., Methods: We conducted an open-label, non-inferiority, randomised, controlled trial at two clinical trial sites in Dhaka, Bangladesh. Healthy infants aged 6 weeks were randomly assigned (1:1:1) using block randomisation, stratified by site, to receive nOPV2 only, nOPV2 plus bOPV, or bOPV only, at the ages of 6 weeks, 10 weeks, and 14 weeks. Eligibility criteria included singleton and full term (≥37 weeks' gestation) birth and parents intending to remain in the study area for the duration of study follow-up activities. Poliovirus neutralising antibody titres were measured at the ages of 6 weeks, 10 weeks, 14 weeks, and 18 weeks. The primary outcome was cumulative immune response for all three poliovirus types at the age of 14 weeks (after two doses) and was assessed in the modified intention-to-treat population, which was restricted to participants with adequate blood specimens from all study visits. Safety was assessed in all participants who received at least one dose of study product. A non-inferiority margin of 10% was used to compare single and concomitant administration. This trial is registered with ClinicalTrials.gov, NCT04579510., Findings: Between Feb 8 and Sept 26, 2021, 736 participants (244 in the nOPV2 only group, 246 in the nOPV2 plus bOPV group, and 246 in the bOPV only group) were enrolled and included in the modified intention-to-treat analysis. After two doses, 209 (86%; 95% CI 81-90) participants in the nOPV2 only group and 159 (65%; 58-70) participants in the nOPV2 plus bOPV group had a type 2 poliovirus immune response; 227 (92%; 88-95) participants in the nOPV2 plus bOPV group and 229 (93%; 89-96) participants in the bOPV only group had a type 1 response; and 216 (88%; 83-91) participants in the nOPV2 plus bOPV group and 212 (86%; 81-90) participants in the bOPV only group had a type 3 response. Co-administration was non-inferior to single administration for types 1 and 3, but not for type 2. There were 15 serious adverse events (including three deaths, one in each group, all attributable to sudden infant death syndrome); none were attributed to vaccination., Interpretation: Co-administration of nOPV2 and bOPV interfered with immunogenicity for poliovirus type 2, but not for types 1 and 3. The blunted nOPV2 immunogenicity we observed would be a major drawback of using co-administration as a vaccination strategy., Funding: The US Centers for Disease Control and Prevention., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: After global oral poliovirus vaccine (OPV) cessation, the Strategic Advisory Group of Experts on Immunization (SAGE) currently recommends a two-dose schedule of inactivated poliovirus vaccine (IPV) beginning ≥14-weeks of age to achieve at least 90% immune response. We aimed to compare the immunogenicity of three different two-dose IPV schedules started before or at 14-weeks of age., Methods: We conducted a randomized, controlled, open-label, inequality trial at two sites in Dhaka, Bangladesh. Healthy infants at 6-weeks of age were randomized into one of five arms to receive two-dose IPV schedules at different ages with and without OPV. The three IPV-only arms are presented: Arm C received IPV at 14-weeks and 9-months; Arm D received IPV at 6-weeks and 9-months; and Arm E received IPV at 6 and 14-weeks. The primary outcome was immune response defined as seroconversion from seronegative (<1:8) to seropositive (≥1:8) after vaccination, or a four-fold rise in antibody titers and median reciprocal antibody titers to all three poliovirus types measured at 10-months of age., Findings: Of the 987 children randomized to Arms C, D, and E, 936 were included in the intention-to-treat analysis. At 10-months, participants in Arm C (IPV at 14-weeks and 9-months) had ≥99% cumulative immune response to all three poliovirus types which was significantly higher than the 77-81% observed in Arm E (IPV at 6 and 14-weeks). Participants in Arm D (IPV at 6-weeks and 9-months) had cumulative immune responses of 98-99% which was significantly higher than that of Arm E (p value < 0.0001) but not different from Arm C., Interpretation: Results support current SAGE recommendations for IPV following OPV cessation and provide evidence that the schedule of two full IPV doses could begin as early as 6-weeks., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier Ltd.)

The conditions in densely populated Bangladesh favor picornavirus transmission, resulting in a high rate of infection in the human population. Data suggest that nonhuman primates (NHP) may play a role in the maintenance and transmission of diverse picornaviruses in Bangladesh. At the Dhaka Zoo, multiple NHP species are caged in close proximity. Their proximity to other species and to humans, both zoo workers and visitors, provides the potential for cross-species transmission. To investigate possible interspecies and intraspecies transmission of picornaviruses among NHP, we collected fecal specimens from nine NHP taxa at the Dhaka Zoo at three time points, August 2007, January 2008, and June 2008. Specimens were screened using real-time PCR for the genera Enterovirus, Parechovirus, and Sapelovirus, and positive samples were typed by VP1 sequencing. Fifty-two picornaviruses comprising 10 distinct serotypes were detected in 83 fecal samples. Four of these serotypes, simian virus 19 (SV19), baboon enterovirus (BaEV), enterovirus 112 (EV112), and EV115, have been solely associated with infection in NHP. EV112, EV115, and SV19 accounted for 88% of all picornaviruses detected. Over 80% of samples from cages housing rhesus macaques, olive baboons, or hamadryas baboons were positive for a picornavirus, while no picornaviruses were detected in samples from capped langurs or vervet monkeys. In contrast to our findings among synanthropic NHP in Bangladesh where 100% of the picornaviruses detected were of human serotypes, in the zoo population, only 15% of picornaviruses detected in NHP were of human origin. Specific serotypes tended to persist over time, suggesting either persistent infection of individuals or cycles of reinfection.

Molecular methods have enabled the rapid identification of new enterovirus (EV) serotypes that would have been untypable using existing neutralizing antisera. Nineteen strains of four new EV types termed EV76 (11 isolates), EV89 (two isolates), EV90 (four isolates) and EV91 (two isolates), isolated from clinical specimens from patients in France (one isolate) and Bangladesh (18 isolates), are described. Nucleotide sequences encoding the VP1 capsid protein (882-888 nt) are less than 65 % identical to the homologous sequences of the recognized human EV serotypes, but within each group the sequences are more than 78 % identical. The deduced amino acid sequences of the complete capsid (P1) region are more than 94 % identical within type but less than 76 % identical to those of the recognized serotypes. For both VP1 and P1, the 19 isolates are monophyletic by type with respect to all other EV serotypes. Using the proposed molecular typing scheme, these data support their identification as four new types within the species Human enterovirus A (HEV-A). In almost all cases, the VP1 sequences were more similar to those of some simian EVs than to the human EVs. Partial 3D sequences of all 19 isolates also clustered within HEV-A; they were monophyletic as a group, but not by type, suggesting that recombination has occurred among viruses of these four types. Partial 3D sequences were more closely related to those of simian EVs than to human viruses in HEV-A. These results suggest that the four new types may represent a new subgroup within HEV-A, in addition to the existing human and simian subgroups.