Concurrent infection of Japanese encephalitis and mixed plasmodium infection.

Dear Sir,

We endorse the diagnosis of Japanese encephalitis virus (JE) infection in the three-year-old male child in Gorakhpur, India,[1] even though the omission of the date of admission of the child in the hospital by the authors is unfortunate. Of course, Gorakhpur district in Uttar Pradesh with a population of 3.62 million is highly endemic for JE, but the incidence of malaria is negligible. During 2010 and 2011, of the 44,084 and 44,579 blood samples taken from cases with fever, only five and three cases, respectively, were found to be infected with Plasmodium falciparum. (National Vector Borne Diseases Control Program, India: Unpublished data).

Mixed Plasmodium infection is widely prevalent in tribal, forested areas with a hyperendemicity for malaria, best exemplified by the states of Jharkhand, Chhattisgarh, Odisha, and in the northeast region of India.[2] Unfortunately, details about any prior stay of the child in such regions have not been provided.[1]

The diagnosis of malaria in this case was based on a rapid diagnostic test (details about the test kit used are not provided). Furthermore, no information has been given about the day during the period of hospitalization when this was done. The ‘gold standard’ is microscopy with a thin and thick smear; different rapid tests are only additional tools, even if they are based on the detection of antigens, enzymes, or plasmodial deoxyribonucleic acid (DNA) by fluorescent staining.[3] Such tests would be useful only for epidemiological studies and would be no guide for treatment of cases with atypical presentations.

Details about the laboratory where the slides taken from the child were sent for substantiation of the dual Plasmodium infection are missing.[1] Although there is no prejudice about the professional competence of the external laboratory where the blood film was sent, it would be important to learn about their standards of internal quality control and external quality assessment. Obviously, reference laboratories such as the National Vector Control Programme would have been more suitable.

The hemoglobin level of 9.5g% on admission, the 12th day of fever, with P. falciparum infection, is intriguing, as P. falciparum infection is accompanied with severe anemia, manifest as a rapid decline in the hemoglobin level. The child, with practically little immunity, would have not survived 10 days of P. falciparum infection.

P.falciparum infection accompanied by the involvement of brain, manifests in a comatose state and in either sluggish or exaggerated deep reflexes. The neurological symptoms could simulate meningitis, epilepsy, acute delirium, intoxication, or heat stroke.[4] On the other hand, altered mental status, which can range from mild confusion to agitation to overt coma, is the major characteristic of JE.[5]

The occurrence of vector-borne diseases is linked with the locally prevalent mosquito species. Gorakhpur district is endemic for JE as only the Culex vishnui group of mosquitoes breed in rice fields which is the main crop. These vectors maintain JE transmission mainly in peridomestic situations. The absence of malaria is due to the fact that Gorakhpur is a flood-prone area. The vector for malaria is Anopheles culicifacies which breeds in sunny and clear water pools without vegetation, which would get washed off in floods.