Surveillance for Nipah virus (NV) was conducted in Thailand's bat population. Immunoglobulin G antibodies to NV were detected with enzyme immunoassay in 82 of 1,304 bats. NV RNA was found in bat saliva and urine. These data suggest the persistence of NV infection in Thai bats.

Background

Rabies virus preferentially involves brainstem, thalamus and spinal cord in human furious and paralytic rabies beginning in the early stage of illness. Nevertheless, rabies patient remains alert until the pre-terminal phase. Weakness of extremities develops only when furious rabies patient becomes comatose; whereas peripheral nerve dysfunction is responsible for weakness in paralytic rabies.

Methods

Evidence of apoptosis and mitochondrial outer membrane permeabilization in brain and spinal cord of 10 rabies patients was examined and these findings were correlated with the presence of rabies virus antigen.

Results

Although apoptosis was evident in most of the regions, cytochrome c leakage was relatively absent in spinal cord of nearly all patients despite the abundant presence of rabies virus antigen. Such finding was also noted in brainstem of 5 patients.

Conclusion

Cell death in human rabies may be delayed in spinal cord and the reticular activating system, such as brainstem, thus explaining absence of weakness due to spinal cord dysfunction and preservation of consciousness.

Background

Rabies is readily diagnosed when it presents as the classic furious form. Paralytic and atypical forms can pose significant problems in diagnosis. Catastrophic incidents included 7 organ transplant recipients who died of rabies recently in United States and Germany. Although rabies remains top in the lists of differential diagnosis of encephalitis in rabies endemic area, its complication may divert physicians from making a relevant management. We encountered an unusual case of paralytic rabies who presented with spontaneous pneumomediastinum.

Case Presentation

A young male presented with fever and dysphagia. There was a history of fluctuating consciousness and aerophobia but they were absent or could not be demonstrated at the time of admission. He exhibited subcutaneous chest wall emphysema and was found to have pneumomediastinum which resulted in surgical intervention. He developed paralysis followed by seizures during postoperative period. Diagnosis was confirmed by demonstration of rabies RNA in saliva during the preterminal phase and by the autopsy. Over 200 hospital staff subsequently received rabies postexposure prophylaxis.

Conclusion

Spontaneous pneumomediastinum can be a rare complication of rabies. It may lead clinicians to perform inappropriate treatment, particularly when phobic spasms are not present and agitation is not prominent. High level of awareness of rabies in any patient with confusion albeit subtle or with any obscure neurological presentations such as difficulty swallowing with no identifiable causes must be borne in mind.

Background

In Thailand, rabies remains a neglected disease with authorities continuing to rely on human death statistics while ignoring the financial burden resulting from an enormous increase in post-exposure prophylaxis. Past attempts to conduct a mass dog vaccination and sterilization program have been limited to Bangkok city and have not been successful. We have used molecular epidemiology to define geographic localization of rabies virus phylogroups and their pattern of spread in Thailand.

Methods

We analyzed 239 nucleoprotein gene sequences from animal and human brain samples collected from all over Thailand between 1998 and 2002. We then reconstructed a phylogenetic tree correlating these data with geographical information.

Results

All sequences formed a monophyletic tree of 2 distinct phylogroups, TH1 and TH2. Three subgroups were identified in the TH1 subgroup and were distributed in the middle region of the country. Eight subgroups of TH2 viruses were identified widely distributed throughout the country overlapping the TH1 territory. There was a correlation between human-dependent transportation routes and the distribution of virus.

Conclusion

Inter-regional migration paths of the viruses might be correlated with translocation of dogs associated with humans. Interconnecting factors between human socioeconomic and population density might determine the transmission dynamics of virus in a rural-to-urban polarity. The presence of 2 or more rabies virus groups in a location might be indicative of a gene flow, reflecting a translocation of dogs within such region and adjacent areas. Different approaches may be required for rabies control based on the homo- or heterogeneity of the virus. Areas containing homogeneous virus populations should be targeted first. Control of dog movement associated with humans is essential.

Surveillance for lyssaviruses was conducted among bat populations in 8 provinces in Thailand. In 2002 and 2003, a total of 932 bats of 11 species were captured and released after serum collection. Lyssavirus infection was determined by conducting virus neutralization assays on bat serum samples. Of collected samples, 538 were either hemolysed or insufficient in volume, which left 394 suitable for analysis. These samples included the following: Pteropus lylei (n = 335), Eonycteris spelaea (n = 45), Hipposideros armiger (n = 13), and Rousettus leschennaulti (n = 1). No serum samples had evidence of neutralizing antibodies when tested against rabies virus. However, 16 samples had detectable neutralizing antibodies against Aravan virus, Khujand virus, Irkut virus, or Australian bat lyssavirus; all were specifically associated with fruit bats P. lylei (n = 15) and E. spelaea (n = 1). These results are consistent with the presence of naturally occurring viruses related to new putative lyssavirus genotypes.