Meningoencephalitis in a 9-year old boy In 2004, a \"9 year old boy is admitted to the hospital in Northern Italy\" from an illness that included a \"1-day history of fever and persistent headache onthe right side.\" The boy had swum in a small \'swimming hole associated with the po River 10 days before the onset of symptoms.\" \"The region was experiencing an unusually hot summer.\" \"The patient\'s temperature was 38c, total leukocyte count his was 13,780/mm3 his reactive protein level was 1.2mg/L He did not have any symptoms of meningitis and his CT scan was normal.\" -on day 2, he developed a stiff neck and became progressively sleepy. A lumbar puncture revealed a total leukocyte count of 6,800/mm3 with 90% neutrophils. csF smears were Gram-stained and were negative for bacteria and fungi.\" on day 3-the Tuc more than tripled and the creactive protein level increased nearly 10x. The patient was started on \"ceftriaxone and corticosteroids\" and transferred to the pediatric ICU. He was \"lethargic and had a scale of He was treated with acyclovir and mannitol and was ed and mechanically ventilated. An \"EEG showed decreased electric activity with short, focal convulsive seizures. Further testing of the csF and blood was done and did not reveal any viruses, bacteria, or fungi. He continued to decline and \"was pronounced dead 6-days after the onset of symptoms.\" on autopsy-no chronic illnesses were discovered. His brain was swollen, had an abnormal appearance, and showed a massive and diffuse inflammatory infiltrate.\" upon further examination, a high number of neutrophils were found and large clusters of cells that resembled amoeba. \"None of the patient\'s friends and relatives who swam in the same water hole on the same day became ill. Nasal swabs from all of them were negative for amoebas.\" Reference From EID, vol 10, no 10, October 2004 1. What is the diagnosis? Name the pathogen that caused the boy\'s illness. 2. What are the incidence and the fatality rate for this disease? 3. How is the disease transmitted? 4. How would you categorize this pathogen? virulent? zoonotic? opportunistic? Solution Answer: 1. Meningoencephalitis in a 9 year old boy: (1) Autopsy revealed massive and diffuse inflammatory infiltrate characterized by a high number of neutrophils, few large clusters of cells that morphologically resembled amoebic vegetative forms, tentatively classified as Entamoeba or Naegleria. It appears to be a case of primary amoebic meningoencephalitis (PAM) caused by Naegleria fowleri. (2) PAM is a rare disease and fatality rate has remained more than 95%. (3) Naegleria fowleri usually infects people when contaminated water enters the body through the nose. Once the amoeba enters the nose, it travels to the brain where it causes PAM, which is usually fatal. Infection typically occurs when people go swimming or diving in warm freshwater places, like lakes and rivers. (4) Naegleria fowleri can be are free living amoeba and can be categor.

1. Meningoencephalitis in a 9-year old boy In 2004, a "9 year old boy is admitted to the hospital
in Northern Italy" from an illness that included a "1-day history of fever and persistent
headache onthe right side." The boy had swum in a small 'swimming hole associated with the
po River 10 days before the onset of symptoms." "The region was experiencing an unusually
hot summer." "The patient's temperature was 38c, total leukocyte count his was 13,780/mm3
his reactive protein level was 1.2mg/L He did not have any symptoms of meningitis and his CT
scan was normal." -on day 2, he developed a stiff neck and became progressively sleepy. A
lumbar puncture revealed a total leukocyte count of 6,800/mm3 with 90% neutrophils. csF
smears were Gram-stained and were negative for bacteria and fungi." on day 3-the Tuc more
than tripled and the creactive protein level increased nearly 10x. The patient was started on
"ceftriaxone and corticosteroids" and transferred to the pediatric ICU. He was "lethargic and
had a scale of He was treated with acyclovir and mannitol and was ed and mechanically
ventilated. An "EEG showed decreased electric activity with short, focal convulsive seizures.
Further testing of the csF and blood was done and did not reveal any viruses, bacteria, or fungi.
He continued to decline and "was pronounced dead 6-days after the onset of symptoms." on
autopsy-no chronic illnesses were discovered. His brain was swollen, had an abnormal
appearance, and showed a massive and diffuse inflammatory infiltrate." upon further
examination, a high number of neutrophils were found and large clusters of cells that resembled
amoeba. "None of the patient's friends and relatives who swam in the same water hole on the
same day became ill. Nasal swabs from all of them were negative for amoebas." Reference
From EID, vol 10, no 10, October 2004 1. What is the diagnosis? Name the pathogen that caused
the boy's illness. 2. What are the incidence and the fatality rate for this disease? 3. How is the
disease transmitted? 4. How would you categorize this pathogen? virulent? zoonotic?
opportunistic?
Solution
Answer:
1. Meningoencephalitis in a 9 year old boy:
(1) Autopsy revealed massive and diffuse inflammatory infiltrate characterized by a high number
of neutrophils, few large clusters of cells that morphologically resembled amoebic vegetative
forms, tentatively classified as Entamoeba or Naegleria.
It appears to be a case of primary amoebic meningoencephalitis (PAM) caused by Naegleria
fowleri.
(2) PAM is a rare disease and fatality rate has remained more than 95%.
(3) Naegleria fowleri usually infects people when contaminated water enters the body through

2. the nose. Once the amoeba enters the nose, it travels to the brain where it causes PAM, which is
usually fatal.
Infection typically occurs when people go swimming or diving in warm freshwater places, like
lakes and rivers.
(4) Naegleria fowleri can be are free living amoeba and can be categorized as opportunistic.
Naegleria fowleri causes the acute and fulminant disease primary amoebic meningoencephalitis
(PAM) typically in immunocompetent children and young adults