Neurovirulence of acute-haemorrhagic-conjunctivitis virus in monkeys

Emerging viral infections of the nervous system

New viral infections of the nervous system have been appearing with great regularity. Some result from the evolution of new agents and others from the entry of viruses into new hosts or environments. The emergence of neurovirulent enteroviruses causing a paralytic poliomyelitis syndrome and rhomboencephalitis represent the evolution of new human viruses. Most emerging viral infections represent movement of an agent into new geographic areas or across species barriers. The transport of neurovirulent strains of West Nile virus into the Western Hemisphere and the penetration of Nipah virus, a newly recognized paramyxovirus, across species barriers from bat to pig to man are examples that are highlighted in this review. The burgeoning human population and the speed and frequency of travel favor the evolution, preservation, and spread of new viral agents.

The Soriano Award Lecture. Emerging infections of the nervous system

The epidemic of acquired immunodeficiency disease [AIDS] has focused interest on the origins of "new" infectious agents. Great plagues are well known from the distant past, but a number of novel diseases affecting the nervous system infections have emerged in recent years. The causes of such new disorders are diverse: whereas rapid mutations of microbes allow the evolution of truly novel agents, the appearance of new diseases is more often due to changes in human or vector populations or changes in societal mores that result in dissemination of preexistent microbes. Examples of recently emerging infections that involve the nervous system include the enterovirus 70 epidemics with poliomyelitis-like disease, the appearance of California virus encephalitis in the midwestern United States, the rapid spread of Lyme disease with its many neurological complications in the eastern United States, and the outbreak of bovine spongiform encephalopathy in the United Kingdom, in addition to the devastating epidemic of human immunodeficiency virus (HIV), which will cause nervous system disease in over half of those infected. As the world population increases and modern transportation brings us closer into a "global village" more new agents will emerge and more will be sustained. Knowledge of the molecular biology and ecology of the agents and awareness of how our actions can alter their behavior are our best defense.

Enterovírus-70 na região metropolitana de São Paulo, Brasil, de 1984 a 1987: aspectos da infecção em períodos epidêmico e endêmico

São apresentados os resultados de estudos sobre o comportamento do Enterovírus-70 (EV-70) na região metropolitana de São Paulo desde sua provável introdução no verão de 1984, determinando extensa epidemia de conjuntivite hemorrágica aguda (C.H.A.), até o final de 1987 abrangendo período em que este agravo foi pouco notado. Na fase epidêmica ocorrida no primeiro trimestre de 1984 foram estudados 291 indivíduos divididos em três grupos denominados A, B e C, o primeiro formado por pessoas atingidas pela C.H.A. e os outros dois por indivíduos não atingidos por este agravo mas que, respectivamente, referiam contato domiciliar com casos de C.H.A. e os que não referiam o citado contato. A demonstração de anticorpos se fez pela técnica de imunofluorescência indireta (IFI) para detectar IgM específico para EV-70 e pela prova de neutralização em cultura de células BHK-21. Verificou-se que 56,7%, 33,3% e 20,6% dos indivíduos pertencentes, respectivamente, aos grupos A, B e C apresentavam anticorpos específicos da classe IgM. No grupo A a faixa etária mais atingida foi a de 10 a 29 anos. No período que vai do fim da primeira e única epidemia até o final de 1987, identificaram-se três casos esporádicos de C.H.A. e 10 pacientes com afecção neurológica aguda associada à infecção recente pelo EV-70. Nove, destes 10 casos, apresentaram paralisia de nervos cranianos, todos evoluindo sem seqüelas clinicamente discerníveis. As formas assintomáticas e os casos esporádicos de C.H.A. e de afecções neurológicas mantiveram a circulação do EV-70 no período não epidêmico.

[Acute hemorrhagic conjunctivitis, in Cuiabá, Mato Grosso, Brazil 1983]

Foi feita investigação de natureza etiológica clínica e laboratorial durante uma epidemia de conjuntivite hemorrágica aguda (CHA), ocorrida em Cuiabá, MT durante os meses de dezembro de 1982 e fevereiro de 1983; atendidos 68 pacientes e colhidos espécimes da conjuntiva, orofaringe e soro. Em 28 pares de soros foram realizados testes de neutralização em tubos de cultura de tecidos para o enterovirus 70 (EV 70) e fixaço do complemento para os adenovirus. Os resultados revelaram conversão sorológica de 89,3% (25 pares de soro) para o EV 70. A Secretaria de Saúde do Estado do Mato Grosso estima que aproximadamente 70% da população tenha sido atingida durante o surto. Não foram observadas evidências de comprometimento neurológico em pacientes de conjuntivite, durante ou logo após o surto.

Neurological complications of acute haemorrhagic conjunctivitis

Forty four cases of the neurological complications of acute haemorrhagic conjunctivitis (AHC) seen in India during 1981 epidemic are reported. The disease predominantly affected adult males. The preceding attack of AHC, a latent period, prodromal symptoms of fever, myalgia and root pains followed by acute onset of lower motor neurone paralysis of limbs and/or cranial nerves formed the classical picture of neurological involvement. The recovery was poor and nearly half of the patients remained severely handicapped. Electrophysiological studies showed early appearance of widespread fibrillations and fasciculations, large polyphasic potentials of increased amplitude and reduced interference pattern. Nerve conduction studies were normal in most of the cases. Cerebrospinal fluid (CSF) examination revealed lymphocytic pleocytosis and rise in protein content. Significant antibody titres against enterovirus type 70 (EV 70) were demonstrated in the serum and the CSF. HLA studies showed low occurrence of A2 and B15 HLA antigens. Muscle biopsies revealed neurogenic atrophy and sural nerve biopsies were histologically unremarkable. The similarities of this disease with poliomyelitis and its pathogenesis are discussed.

A study of the neurological disorder associated with acute haemorrhagic conjunctivitis due to enterovirus 70

Ninety cases of the neurological manifestations associated with acute haemorrhagic conjunctivitis caused by Enterovirus 70 (EV 70) are reported. The patients were seen during the widespread epidemics in 1971 and 1981. Male adults were predominantly affected by a "polio-like" paralysis of the limbs and/or cranial nerves. Root pains were often complained of early in the disease. In the absence of a necropsy, clinical and neurophysiological examinations helped to localise the lesions. Significant antibody titres against EV 70 were demonstrated in the serum and more relevantly in the CSF. Though other viruses can cause sporadic and epidemic conjunctivitis and similar paralysis independently, the combination of a haemorrhagic conjunctivitis and a neurological disease mostly simulating poliomyelitis is caused by EV 70 alone. It is therefore suggested that this combination be called "Enterovirus 70 disease". Because of its neurovirulence, it is important to identify this virus at the very beginning of an epidemic of conjunctivitis, so as to limit its spread by strict public health measures.

Adult polio-like syndrome following Enterovirus 70 conjunctivitis (natural history of the disease)

During the Indian EV 70 conjunctivitis epidemic in 1981, 79 patients with neurological complications were evaluated by clinical, electrophysiological, histopathological and virological studies. The disease was heralded by an attack of conjunctivitis and was followed, after a variable latent period, by a pre-paralytic, paralytic, and post-paralytic stage of slow recovery. The above events occurred in an orderly sequence. The paralysis affected the cranial nerves, limbs or both. The clinical course closely simulated poliomyelitis, without any evidence of radiculopathy or myelopathy. Cranial nerve palsies were seen in approximately half of the patients. The electrophysiological and histologicl studies pointed towards the affection of anterior horn cells. The raised neutralizing antibody titres to Enterovirus 70, confirmed the aetiology of the disease. On the available data, we believe that this nosological entity should be considered under the general title of "polio-like syndrome" following EV 70 conjunctivitis. On account of two epidemics in 1971 and 1981 with unfavourable prognosis and high resultant disability, and because of lack of specific therapy, it has become imperative to develop, as a top priority, a vaccine for immunization.

Radiculomyelitis complicating acute haemorrhagic conjunctivitis. A clinical study

Fourteen patients with radiculomyelitis following acute haemorrhagic conjunctivitis (AHC) were seen in Bangkok during October to December 1974. Most patients developed weakness of extremities 2 weeks after AHC. Prodromal symptoms consisted of fever and malaise for a few days, followed by the acute onset of root pain in the legs and flaccid paralysis. Knee and ankle reflexes were absent or diminished. Cerebrospinal fluid examination revealed lymphocytosis and an increase in protein. Electromyographic findings were consistent with anterior horn cell or motor root lesions. Ten of the 12 cases in which virological studies were performed showed definite serological evidence of AHC virus infection. Six patients received corticosteroid treatment but apart from relief of pain no significant improvement was seen. Motor weakness in 10 patients was less at the end of 2 months, but in 4 it remained unchanged. The occurrence of disabling neurological sequelae calls for effective public health control of AHC outbreak.

Neurologic complications with elevated antibody titer after acute hemorrhagic conjunctivitis

Nine patients with polyradiculomyeloneuropathy after acute hemorrhagic conjunctivitis (AHC) infection were studied serologically. All except one patient had neutralization titers larger than or equal to 1:16 against the prototype J670/71 strain of AHC virus in at least one of their serum samples. The development of a significant fourfold rise in antibody titer against AHC virus occurred in one of the patients who developed neurologic complications five days after the onset of AHC infection.