Emerging infectious diseases involving zoonosis have become important global health problems. The 1998 outbreak of severe febrile encephalitis among pig farmers in Malaysia caused by a newly emergent paramyxovirus, Nipah virus, is a good example. This disease has the potential to spread to other countries through infected animals and can cause considerable economic loss. The clinical presentation includes segmental myoclonus, areflexia, hypertension, and tachycardia, and histologic evidence includes endothelial damage and vasculitis of the brain and other major organs. Magnetic resonance imaging has demonstrated the presence of discrete high-signal-intensity lesions disseminated throughout the brain. Nipah virus causes syncytial formation in Vero cells and is antigenically related to Hendra virus. The Island flying fox (Pteropus hypomelanus; the fruit bat) is a likely reservoir of this virus. The outbreak in Malaysia was controlled through the culling of >1 million pigs.
NMDAR encephalitis may be more common among non-Caucasians. A population-based study was conducted to estimate its incidence in Sabah, Malaysia, where the population consists predominantly of Austronesians (84%), and with a Chinese minority. Registries of NMDAR encephalitis at neurology referral centers were reviewed for case ascertainment. The annual incidence was 2.29/million (Austronesians: 2.56/million, Chinese: 1.31/million). Among pediatric population, the incidence was: Austronesians: 3.63/million, Chinese: 2.59/million. Our study demonstrated a higher incidence of NMDAR encephalitis among Austronesians than the predominantly Caucasian populations in Europe (0.5-0.9/million; pediatric: 0.7-1.5/million). Racial and genetic factors may contribute to risks of developing NMDAR encephalitis.
Four hundred and six AIDS patients were recruited in this retrospective study. The seroprevalence of toxoplasmosis among 406 AIDS patients was 208 (51.2%). Their age ranged from 17 to 74 years with a median of 35 years. The majority of patients were males 172 (82.6%), Malays 99 (47.5%), single 109 (52.4%), unemployed 99 (47.6%) and heterosexual with commercial sex workers (CSW) 97 (46.6%) as the risk marker to HIV infection. Thirty-one (14.9%) of 208 AIDS-related toxoplasmosis were diagnosed as active toxoplasmic encephalitis. The most common clinical manifestation was headache (67.7%). The CT scan findings showed most lesions to be multiple (87.5%), hypodense (66.7%), and in frontal region (41.7%). Twenty-two (71%) patients had chronic (latent) Toxoplasma infection as evidenced by seropositivity for anti-Toxoplasma (IgG) antibody. They were statistically significant in the association between CD4 count and toxoplasmic encephalitis (P = 0.019; OR = 2.6; 95% CI = 1.14-6.02). After the initial six weeks of anti-TE therapy, relapsing toxoplasmic encephalitis was detected in 9.7% in this study.
In the 1950s, Bickerstaff and Fisher independently described cases with a unique presentation of ophthalmoplegia and ataxia. The neurological features were typically preceded by an antecedent infection and the majority of patients made a spontaneous recovery. In the cases with Bickerstaff brainstem encephalitis, there was associated altered consciousness and in some, hyperreflexia, in support of a central pathology whereas in Fisher syndrome, patients were areflexic in keeping with a peripheral aetiology. However, both authors recognised certain similarities to Guillain-Barré syndrome such as the presence of peripheral neuropathy and cerebrospinal fluid albuminocytological dissociation. The discovery of immunoglobulin G anti-GQ1b antibodies in patients with Fisher syndrome and later in Bickerstaff brainstem encephalitis was crucial in providing the necessary evidence to conclude that both conditions were in fact part of the same spectrum of disease by virtue of their common clinical and immunological profiles. Following this, other neurological presentations that share anti-GQ1b antibodies emerged in the literature. These include acute ophthalmoparesis and acute ataxic neuropathy, which represent the less extensive spectrum of the disease whereas pharyngeal-cervical-brachial weakness and Fisher syndrome overlap with Guillain-Barré syndrome represent the more extensive end of the spectrum. The conditions can be referred to as the 'anti-GQ1b antibody syndrome'. In this review, we look back at the historical descriptions and describe how our understanding of Fisher syndrome and Bickerstaff brainstem encephalitis has evolved from their initial descriptions more than half a century ago.
We retrospectively reviewed 419 HIV/AIDS patients in Hospital Kuala Lumpur from 1994 to 2001. In the male group, the age range was 20-74, with a mean age 37 years, while in the female group it was 17-63, with a mean age of 33 years. With regard to age group, it was found that the preponderant age group was 25-34 years. The majority of male subjects were Chinese (52.5%), single (56.3%), and unemployed (55.1%), whereas the females were Malay (42.3%), married (79.5%), and non-laborer (64.1%). Also, both groups resided in Kuala Lumpur and had heterosexual contact as the leading cause of HIV transmission. More than half of the patients had CD4 cell counts of <200 cells/cumm. We found that the acquisition of HIV infection via intravenous drug use (IDU) was directly related to the incidence of tuberculosis infection (P < 0.05). Further analysis showed HIV-related tuberculosis with IDU was also dependently correlated with occupational status (unemployed) (P < 0.05). The four main AIDS-defining diseases include tuberculosis (48%), Pneumocystis carinii pneumonia (13%), toxoplasmic encephalitis (11%), and cryptococcal meningitis (7%); in addition, 53% of these patients were found to have CD4 cell counts of less than 200 cells/cumm at the time of diagnosis.
Nipah virus, a paramyxovirus related to Hendra virus, first emerged in Malaysia in 1998. Clinical presentation ranges from asymptomatic infection to fatal encephalitis. Malaysia has had no more cases since 1999, but outbreaks continue to occur in Bangladesh and India. In the Malaysia-Singapore outbreak, transmission occurred primarily through contact with pigs, whereas in Bangladesh and India, it is associated with ingestion of contaminated date palm sap and human-to-human transmission. Bats are the main reservoir for this virus, which can cause disease in humans and animals. There are currently no effective therapeutics, and supportive care and prevention are the mainstays of management.
The Nipah virus is a newly identified paramyxovirus responsible for an outbreak of fatal encephalitis in Malaysia and Singapore. This paper reports the follow up clinical and magnetic resonance imaging findings in 22 affected subjects. Of 13 patients with encephalitis, one died, one was lost to follow up, and seven recovered. Among the four remaining patients, one had residual sixth nerve palsy, another suffered from severe clinical depression, and a third patient had evidence of retinal artery occlusion. One patient with delayed onset Horner syndrome had a single lesion in the cervical spinal cord. The brain magnetic resonance findings were stable or improved in nine patients over 18 months of follow up. Among a second group of nine asymptomatic seropositive abattoir workers, magnetic resonance examination in seven subjects revealed discrete small lesions in the brain; similar to those detected in encephalitis patients. These findings suggest that in addition to encephalitis, the newly discovered Nipah virus affects the spinal cord and the retina. Late clinical and radiological findings can occur in Nipah virus infections as with other paramyxoviruses.