Kolkata, Sep 9 (IANS): Following the death of a father and son within 12 hours here due to suspected dengue, civic authorities ruled out the vector-borne disease as the cause of the son's death.

The authorities also claimed the father may have been infected with the disease outside the state. Ghosh's relatives, however, have alleged the duo died from dengue based on test reports.

Fifty-three-year-old Siddharth Ghosh of Kasba near south Kolkata passed away at a private hospital on September 7 at 3 a.m. while his 13-year old son Deep died on the same day around 1.30 p.m. at the Institute of Child Health.

Deep's death certificate from the Institute of Child Health says "cardiorespiratory failure in a case of severe dengue with encephalitis in a known case of hypothyroidism".

Kolkata Municipal Corporation's member mayor in council (health) Atin Ghosh said the father was depressed because of his son's epilepsy and the deaths could have been linked to those conditions.

"There is a travel history behind the deaths. Siddharth had gone to Chennai for treatment and contracted fever from there," Ghosh on Saturday said, adding everything is being done to prevent dengue cases.