Naegleria fowleri: Sources of infection, pathophysiology, diagnosis, and management; a review

Abstract

Naegleria fowleri, a thermophilic flagellate amoeba known as a “brain‐eating” amoeba, is the aetiological agent of a perilous and devastating waterborne disease known as primary amoebic meningoencephalitis (PAM), both in humans as well as in animals. PAM is a rare but fatal disease affecting young adults all around the world, particularly in the developed world but recently reported from developing countries, with 95%–99% mortality rate. Swimmers and divers are at high risk of PAM as the warm water is the most propitious environment adapted by N. fowleri to cause this infection. Infective amoeba in the trophozoite phase enter the victim's body through the nose, crossing the cribriform plate to reach the human brain and cause severe destruction of the central nervous system (CNS). The brain damage leads to brain haemorrhage and death occurs within 3–7 days in undiagnosed cases and maltreated cases. Though the exact pathogenesis of N. fowleri is still not known, it has exhibited two primary mechanisms, contact‐independent (brain damage through different proteins) and contact‐dependent (brain damage through surface structures food cups), that predominantly contribute to the pathogen invading the host CNS. For the management of this life‐threatening infection different treatment regimens have been applied but still the survival rate is only 5% which is ascribed to its misdiagnosis, as the PAM symptoms closely resembled bacterial meningitis. The main objectives of this review article are to compile data to explore the sources and routes of N. fowleri infection, its association in causing PAM along with its pathophysiology; latest techniques used for accurate diagnosis, management options along with challenges for Pakistan to control this drastic disorder.

Primary Amebic Meningoencephalitis Related to Groundwater in Costa Rica: Diagnostic Confirmation of Three Cases and Environmental Investigation

“…Epidemiologic studies of PAM indicate an estimate of 300-440 cases worldwide [3,6], with more than one third of the cases diagnosed in the United States [7]. However, this number may not exactly reflect the real number as some researchers propose an underestimation of the disease of up to 50% in this country, even when using well-established diagnostic methodologies and researchers with huge knowledge in different aspects related to PAM.…”

Laurinterol from Laurencia johnstonii eliminates Naegleria fowleri triggering PCD by inhibition of ATPases

“…Naegleria fowleri infects humans by passing the nerves and entering the cribiform plate. After that, the amoebae have free entrance to the brain causing inflammation and necrosis 2 , 6 – 8 . Hence, the fulminant nature of this infection which normaly manifests in the patient with symptons such as intense headache, temperature, seizures and stiff neck.…”

“…Hence, the fulminant nature of this infection which normaly manifests in the patient with symptons such as intense headache, temperature, seizures and stiff neck. In the final stage of the disease, patients have been reported to suffer from hallucinations and paralysis previous reaching coma and death 6 – 8 . Furthermore, the average time of symptoms appearance after infection starts 1–9 days after exposure to contaminated water sources whereas patient death average is 1–18 after symptoms begin 4 , 9 .…”

Isolation and Identification of Naegleria Species in Irrigation Channels for Recreational Use in Mexicali Valley, Mexico

“…Accordingly, PAM is considered a serious public health problem due to the previously mentioned high mortality rate [ 7 , 10 , 11 ]. Interestingly, a recent study showed that in Pakistan between 2008 and 2017, more than 100 cases were reported [ 12 ].…”

“…In Mexico, around 11 cases of PAM have been reported from 1984 to 2007 [ 12 , 13 , 14 , 15 , 16 , 17 ]. Unfortunately, there are many cases underdiagnosed around the world due to lack of awareness of the disease or the similarity of clinical symptoms with other more common central nervous systemdiseases such as bacterial meningitis and viral encephalitis [ 6 , 18 ].…”