Molecular and seroepidemiologic studies of Enterovirus 71 infection in the State of Pará, Brazil

In many countries, the Enterovirus 71 (EV-71) Picornaviridae family is associated to hand, foot and mouth disease in addition to acute neurological diseases while in Brazil these viruses are more closely associated to the latter group. The aim of this research was to use the first EV-71 isolate of the Northern region of Brazil in molecular and seroepidemiologic studies. Two (2.2%) out of 88 stool samples (44 cases of AFP), collected from January 1998 to December 2000 were positive for EV-71 isolation (73442/PA/99). Nucleotide sequence of the gen that codifies the VP1 protein showed that isolate 73442/PA/99 was similar to the EV-71 strains belonging to genotype B - more closely identified with EV-71 from North America. Neutralization test with 389 sera samples collected from January 1998 to November 2001, from individuals ranging from 0 to 15 years of age living in the city of Belém, State of Pará showed the following results in relation to isolate 73442/PA/99 and prototype BrCr: a total of 207 individuals (53.2%) had neutralization antibodies to both viruses, 167 (42.9%) had no antibodies and 15 showed the presence of neutralizing antibodies to one of the two viruses. Only 20.2% of the children aged 0 to 3 had neutralizing antibodies to EV-71, indicating that these children were more susceptible to the infection. Both the seroprevalence study and VP1 sequencing were important to demonstrate the spread and the molecular pattern of the EV-71 circulating in the Northern Region of Brazil.

Evaluation of enterovirus 71 immune status in São Paulo state, Brazil

Antibodies to Enterovirus 71 (EV71) were evaluated in São Paulo State during 1999-2005. The titer of neutralizing antibodies against EV71 was determined by microneutralization assay, and a titer of > 1:8 was defined as indicative of protected immunity. Neutralizing antibodies to EV71 were observed in 12.4% (55/442) of sera samples, a low protective rate, suggesting that EV71 infection is uncommon in this region, but that there is a relatively high susceptibility to EV71 related diseases, which is worrying considering the recent Asian outbreaks. Also, a significant location-specific difference in seropositivity was observed. Neutralizing antibodies to EV71 were observed in 8.7% (21/241) of São Paulo metropolitan area sera samples, and 16.9% (34/201) of the sera samples from other municipalities. A high number of Brazilian residents live in country and coastal areas without adequate access to piped water or sanitation. This situation may contribute to the EV71 dissemination in these zones. The analysis of environmental samples could possibly make a valuable contribution to studies on the epidemiology of EV71.

Neutralizing Antibodies to Enterovirus 71 in Belém, Brazil

Non-polio enteroviruses (Coxsackievirus A, Coxsackievirus B, Echovirus and EV 68-72) which belong to the enterovirus (EV) genus, Picornaviridae family, may be responsible for acute flaccid paralysis, aseptic meningitis, myocarditis, hepatitis, pleurodinia, neonatal sepsis, hand, foot and mouth disease (HFMD) even though 50-80% of infections are asymptomatic. EV 71 has been responsible for outbreaks and epidemics of HFMD and acute neurologic disease justifying its study in our country. The aim of this study was to detect neutralizing antibodies (NtAb) to EV 71 in individuals up to 15 years of age living in Belém, State of Pará, northern Brazil. Serum samples from 238 patients attending the Virology Sector of Evandro Chagas Institute in Belém, Brazil, were analyzed using microneutralization tests that included RD cells and BrCr strain. Overall 40.8% (97/238) of tested samples had NtAb to EV 71. Regarding the distribution per age group, 85.2% (92/108) of patients aged 0-3 years had no NtAb to this virus and 69.2% of those 12 to15 years of age were seropositive. These results confirm that EV 71 infection occurs in the city of Belém; and that a high rate of individuals in this study were infected aged 3 years and over and, when aged 15 years nearly 70% had EV 71 NtAb.

Specific detection of enterovirus 71 directly from clinical specimens using real-time RT-PCR hybridization probe assay

Enterovirus 71 (EV71) is one of the main causative agents of hand, foot and mouth disease (HFMD) in young children. Infections caused by EV71 could lead to many complications, ranging from brainstem encephalitis to pulmonary oedema, resulting in high mortality. Thus, rapid detection of the virus is required to enable measures to be implemented in preventing widespread transmission. Based on primers and probes targeting at the VP1 region, a real-time reverse-transcriptase polymerase chain reaction (RT-PCR) hybridization probe assay was developed for specific detection of EV71 from clinical specimens. Quantitative analysis showed that the assay was able to detect as low as 5 EV71 viral copies and EV71 was detected from 46 of the 55 clinical specimens obtained from pediatric patients suffering from HFMD during the period from 2000 to 2003 in Singapore. This study showed that the single tube real-time RT-PCR assay developed in this study can be applied as a rapid and sensitive method for specific detection of EV71 directly from clinical specimens. (c) 2005 Elsevier Ltd. All rights reserved.

Echovirus 4 associated to hand, foot and mouth disease

Hand, foot and mouth disease (HFMD) is a contagious enteroviral infection occurring primarily in children and characterized by vesicular palmoplantar eruptions and erosive stomatitis. Echovirus 4 (EV-4) has been commonly associated with aseptic meningitis. The association of HFMD with EV-4 has not been reported previously. Two samples of a 14-month child who presented mild fever, sores in the mouth, rash with blisters on the palm of hands and soles of feet were sent to Enteric Viruses Laboratory of Adolfo Lutz Institute. Clinical samples were inoculated in three different cell lines, and those which presented cytopathic effect (CPE), were submitted to Indirect Immunofluorescence Assay (IFA) and "one step" RT-PCR. Agarose gel electrophoresis from RT-PCR product, showed a product with 437 bp, which is characteristic of Enterovirus group. Echovirus 4 was identified by IFA. Although HFMD is a viral infection associated mainly with Enterovirus 71 (HEV-71) and Coxsackievirus A16 (CV-A16), our results demonstrate a diversity of serotype related to HFMD and stress the importance of epidemiological surveillance to this disease and its complications.

Comparative pathogenicity of Coxsackievirus A16 circulating and noncirculating strains in vitro and in a neonatal mouse model

An enterovirus 71 (EV71) vaccine for the prevention of hand, foot, and mouth disease (HMFD) is available, but it is not known whether the EV71 vaccine cross-protects against Coxsackievirus (CV) infection. Furthermore, although an inactivated circulating CVA16 Changchun 024 (CC024) strain vaccine candidate is effective in newborn mice, the CC024 strain causes severe lesions in muscle and lung tissues. Therefore, an effective CV vaccine with improved pathogenic safety is needed. The aim of this study was to evaluate the in vivo safety and in vitro replication capability of a noncirculating CVA16 SHZH05 strain. The replication capacity of circulating CVA16 strains CC024, CC045, CC090 and CC163 and the noncirculating SHZH05 strain was evaluated by cytopathic effect in different cell lines. The replication capacity and pathogenicity of the CC024 and SHZH05 strains were also evaluated in a neonatal mouse model. Histopathological and viral load analyses demonstrated that the SHZH05 strain had an in vitro replication capacity comparable to the four CC strains. The CC024, but not the SHZH05 strain, became distributed in a variety of tissues and caused severe lesions and mortality in neonatal mice. The differences in replication capacity and in vivo pathogenicity of the CC024 and SHZH05 strains may result from differences in the nucleotide and amino acid sequences of viral functional polyproteins P1, P2 and P3. Our findings suggest that the noncirculating SHZH05 strain may be a safer CV vaccine candidate than the CC024 strain.

Forme atipiche di malattia mani-piedi-bocca: La nostra esperienza

Introduzione: La malattia mani-piedi-bocca è una patologia infettiva tipica della prima infanzia causata dagli enterovirus, in particolare i sierotipi Coxsackievirus A16 ed Enterovirus 71. A partire dal 2008, ne è stata descritta un’epidemia da Coxsackievirus A6, in genere accompagnata da febbre elevata e che si distingue per lo sviluppo di piccole vescicole che progrediscono a lesioni vescicolo-bollose e a bolle vere e proprie. Inoltre, nei pazienti affetti da dermatite atopica, le lesioni tendono a localizzarsi sulle aree eczematose. Abbiamo quindi svolto uno studio osservazionale prospettico per descrivere le caratteristiche cliniche delle forme atipiche di malattia mani-piedi-bocca. Metodi: Sono stati arruolati i pazienti affetti da una forma atipica di malattia mani-piedi-bocca giunti consecutivamente presso l’Ambulatorio di Dermatologia Pediatrica del Policlinico S.Orsola-Malpighi di Bologna tra gennaio 2012 e febbraio 2014. Abbiamo valutato distribuzione, tipologia ed estensione delle lesioni. In un gruppo di pazienti è stata inoltre eseguita l’identificazione virale sul fluido vescicolare. Risultati: Abbiamo arruolato 47 pazienti (68% maschi) con un’età mediana di 22 mesi. Sono stati individuati 3 aspetti clinici principali: 1) forma acrale (distribuzione delle lesioni prevalentemente acrale), nel 62% dei soggetti; 2) eczema coxsackium (lesioni localizzate su aree eczematose), nel 23% dei soggetti; 3) forma diffusa (estensione delle lesioni al tronco), nel 15% dei soggetti. Inoltre, nell’80% circa dei pazienti si riscontravano macule purpuriche acrali, circa la metà dei pazienti aveva lesioni con aspetto purpurico e il 72% un interessamento dei glutei. In 9 su 11 soggetti genotipizzati è stato isolato il Coxsackievirus A6. Conclusioni: Questo studio ha permesso di descrivere tre fenotipi di malattia mani-piedi-bocca atipica, che deve essere correttamente identificata al fine di non porre diagnosi errate quali varicella, eczema herpeticum, vasculiti, impetigine, e di potere così procedere ad una gestione appropriata della patologia.

Polioviruses and other enteroviruses isolated from faecal samples of patients with acute flaccid paralysis in Australia, 1996-2004

Background: Acute flaccid paralysis (AFP) is the most common clinical presentation of acute poliovirus infection, occurring in 0.1-1% of infected cases. AFP surveillance has been used world-wide to monitor the control and eradication of circulating wild poliovirus. This study aims to review the significance of all enteroviruses, including polioviruses, isolated from patients with AFP in Australia between 1996 and 2004. Methods: We undertook a retrospective review of all notified cases of AFP, aged 0-15 years and resident in Australia at the time of notification. We reviewed all available clinical and virological data for these cases and all records of the Polio Expert Committee, which determined the final classification for all cases. Results: There were 335 notified cases that satisfied the case definition for AFP, 162 (48%) of whom had at least one faecal sample tested. Enteroviruses isolated from the faeces of 26 (16%) of the 162 cases were Coxsackie A24, Coxsackie B5, enterovirus 71, enterovirus 75, echovirus 9, echovirus 11 and echovirus 18. In addition, one or more polioviruses were isolated from the faeces of seven patients. Six of seven polioviruses were characterised as Sabin-like, one was not characterised, but all were considered to be incidental isolates. Five of these cases were classified as infant botulism, one case as transverse myelitis and one as a focal mononeuropathy. Conclusion: With the eradication of circulating wild polioviruses, other enteroviruses are being more commonly identified as the cause of polio-like illnesses. In the polio end game, when there is increased testing for polioviruses, it is important to consider infant botulism as a differential diagnosis in cases presenting with AFP.

Emerging viral diseases of South-East Asia and the Western Pacific: A brief review

Over the past 6 years, a number of zoonotic and vectorborne viral diseases have emerged in Southeast Asia and the Western Pacific. Vectorborne disease agents discussed in this article include Japanese encephalitis, Barmah Forest, Ross River, and Chikungunya viruses. However, most emerging viruses have been zoonotic, with fruit bats, including flying fox species as the probable wildlife hosts, and these will be discussed as well. The first of these disease agents to emerge was Hendra virus, formerly called equine morbillivirus. This was followed by outbreaks caused by a rabies-related virus, Australian bat lyssavirus, and a virus associated with porcine stillbirths and malformations, Menangle virus. Nipah virus caused an outbreak of fatal pneumonia in pigs and encephalitis in humans in the Malay Peninsula. Most recently, Tioman virus has been isolated from flying foxes, but it has not yet been associated with animal or human disease. Of nonzoonotic viruses, the most important regionally have been enterovirus 71 and HIV.

Eccema coxsackium y otra presentación atípica de la enfermedad de mano-pie-boca

La enfermedad de mano-pie-boca (EMPB) es una de las enfermedades exantemáticas más frecuentes en niños menores de cinco años, generalmente producida por los virus Coxsackie A16 y enterovirus 71. En los últimos años se están observando manifestaciones dérmicas diferentes a la habitual causadas por serotipos menos frecuentes como el Coxsackievirus A6. Los pacientes con la EMPB por Coxsakievirus A6 presentan fiebre y síntomas sistémicos como la EMPB típica, pero tienen una manifestación cutánea más grave, pudiendo simular un cuadro Gianotti Crosti-like, o, incluso, un eccema herpeticum. En estos casos, recomendamos analizar el serotipo de enterovirus para prevenir pruebas diagnósticas innecesarias o tratamientos antivirales inapropiados. Presentamos dos casos en niños menores de cinco años, de presentación atípica de EMPB, atendidos en nuestro Servicio de Urgencias. Ambos referían como antecedente padecer dermatitis atópica.

H-1-NMR structural studies of a cystine-linked peptide containing residues 71-93 of transthyretin and effects of a Ser84 substitution implicated in familial amyloidotic polyneuropathy

The Ile-->Ser84 substitution in the thyroid hormone transport protein transthyretin is one of over 50 variations found to be associated with familial amyloid polyneuropathy, a hereditary type of lethal amyloidosis. Using a peptide analogue of the loop containing residue 84 in transthyretin, we have examined the putative local structural effects of this substitution using H-1-NMR spectroscopy. The peptide, containing residues 71-93 of transthyretin with its termini linked via a disulfide bond, was found to possess the same helix-turn motif as in the corresponding region of the crystallographically derived structure of transthyretin in 20% trifluoroethanol (TFE) solution. It therefore, represents a useful model with which to examine the effects of amyloidogenic substitutions. In a peptide analogue containing the Ile84-->Ser substitution it was found that the substitution does not greatly disrupt the overall three-dimensional structure, but leads to minor local differences at the turn in which residue 84 is involved. Coupling constant and NOE measurements indicate that the helix-turn motif is still present, but differences in chemical shifts and amide-exchange rates reflect a small distortion. This is in keeping with observations that several other mutant forms of transthyretin display similar subunit interactions and those that have been structurally analysed possess a near native structure. We propose that the Ser84 mutation induces only subtle perturbations to the transthyretin structure which predisposes the protein to amyloid formation.

Experimental study of phase equilibria in the "FeO"-ZNO-(CaO+SiO2) system with the CaO/SiO2 weight ratio of 0.71 at metallic iron saturation

The pseudoternary section FeO-ZnO-(CaO + SiO2) with a CaO/SiO2 weight ratio of 0.71 in equilibrium with metallic iron has been experimentally investigated in the temperature range from 1000 degreesC to 1300 degreesC (1273 to 1573 K). The liquidus surface in this pseudoternary. section has been determined in the composition range of 0 to 33 wt pct ZnO and 30 to 70 wt pct (CaO + SiO2)The system contains primary-phase fields of wustite (FexZn1-xO1+y), zincite (ZnzFe1-zO), fayalite (FewZn2-wSiO4), melilite (Ca2ZnuFe1-uSi2O7), and pseudowollastonite (CaSiO3). The phase equilibria involving the liquid phase and the solid solutions have also been measured.