The malarial parasite that has caused recent outbreaks of Monkey malaria in humans is
1. Plasmodium berghei
2. Plasmodium vivax
3. Plasmodium knowlesi
4. Plasmodium malariae

Introduction

In recent years, Plasmodium knowlesi, a parasite once thought to primarily infect monkeys, has emerged as a significant cause of malaria in humans. Known as “Monkey Malaria,” infections with P. knowlesi have been reported in Southeast Asia, raising concerns due to its rapid replication rate and potential for severe disease.

What Is Plasmodium knowlesi?

Plasmodium knowlesi is a zoonotic malaria parasite that naturally infects macaque monkeys such as the long-tailed macaque (Macaca fascicularis) and pig-tailed macaque (Macaca nemestrina). The parasite is transmitted through the bite of Anopheles mosquitoes, particularly those found in forested areas.

How It Infects Humans

Human infections typically occur in regions where people live or work near forests inhabited by macaques. P. knowlesi has a 24-hour replication cycle, which means it can cause rapid increases in parasitemia, leading to severe illness if not promptly treated.

Symptoms of Monkey Malaria

Symptoms of P. knowlesi malaria can resemble those caused by other Plasmodium species:

• High fever with chills

• Headache

• Muscle pain

• Fatigue

• Nausea and vomiting

If left untreated, it may lead to organ failure or even death due to its aggressive replication.

Diagnosis and Treatment

Accurate diagnosis is critical since P. knowlesi infections are often misidentified as P. malariae under the microscope. Molecular methods such as PCR are more reliable for confirmation. Treatment usually involves antimalarial drugs like artemisinin-based combination therapies (ACTs).

Public Health Significance

With increasing human encroachment into forested habitats, the risk of zoonotic malaria transmission is growing. Monitoring, early diagnosis, and vector control are key to preventing future outbreaks.

Conclusion

Plasmodium knowlesi is an emerging threat that underscores the importance of zoonotic disease surveillance and integrated health strategies. Awareness and early treatment can save lives and prevent the spread of monkey malaria in humans.