AIIMS researchers have sounded a note of caution after finding the presence of malarial parasite 'Plasmodium knowlesi' in the north Indian population, while doing a study on patients with Acute Febrile Illnesses (AFI) and pathogens causing them.

The presence of the zoonotically transmitted malaria parasite was found during the study of Acute Febrile Iillnesses and causative pathogens in cerain patients admitted in AIIMS from July 2017 to September 2018.

The All Indian Institute of Medical Sciences (AIIMS) researchers from the Department of Biochemistry along with clinicians from the Department of Medicine were involved in the study on the pathogens causing severe fever.

A zoonotic disease is a disease that can be spread/jump from animals to humans, and vice versa. It can be caused by viruses, bacteria, parasites, and fungi.

It is necessary to understand how zoonotic diseases spread, and the way they infect humans, given the fact that the world is at present battling novel coronavirus that has emerged from bats.

Plasmodium knowlesi is a malaria parasite found in nature in long-tailed and pig-tailed macaques.

The team is led by Pragyan Acharya, Associate Professor, Department of Biochemistry, and comprises Manish Soneja from the Department of Medicine, along with Rajendra Mandage, Atreyi Pramanik, Parul Kodan, Vinod Sinha, Shivam Pandey and R.M. Pandey.

"The major lesson from this study is that zoonotic parasites are all around us -- therefore maintaining a clean environment and following specific guidelines for the prevention of these diseases are important," Acharya told IANS.

"A major reason for zoonotic pathogens' effect on our lives is because we are encroaching the space of their animal hosts -- massive decline in forest cover and consequent depleted habitats," Acharya added.

"However, this pathogen is not commonly tested during diagnosis, possibly due to its low prevalence and absence of rapid diagnostic methods."

The researchers said that their study shows the presence of the zoonotic parasite in states of Uttar Pradesh, Haryana, and Delhi. An earlier study at AIIMS had shown its presence in the Andaman and Nicobar Islands.

According to the World Health Organisation, the parasite can give rise to daily fever spikes 9-12 days after the infection. Severe infection may lead to organ failure as well.

Acharya and her team also found that simultaneous pathogenic infections in patients with fever can occur, influencing the severity of disease.

The team found that malaria can exist with other co-infecting pathogens like dengue virus and bacterial species Leptospira and Orientia Tsutsugamushi.

In tropical countries like India, acute febrile illnesses comprise a group of infections with similar clinical presentations such as fever, malaise, bodyache, chills, hepatic and renal dysfunction, and CNS effects.

It is often difficult to distinguish between the causative agents of AFI, which can be bacterial, parasitic, or viral.

Therefore, these pathogens may infect individuals at the same time and lead to modulation of immune responses, change treatment outcomes, and affect disease severity. The correct diagnosis of the infective agent causing fever is thus very important to ensure the right treatment.

The study results ask us to be vigilant about the possibility of multiple pathogenic causes of fever, and to maintain the habitats and ecosystems of animals, the AIIMS researchers added.