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Volume 32, Number 9—September 2026
Synopsis
Epidemiology of and Risk Factors for Amebic Meningoencephalitis, Kerala, India, 2025
Harikumar Sivanandan1, Jeromie Wesley Vivian Thangaraj1, Ala Saritha2, Anitha Bhaskar2, Aravind Reghukumar2, Asuma A. Rahim2, Bindu Vadakkayil2, Chintha Sujatha2, Karthika Meenakshy Amma2, Manoj Arayakandy Thali2, Prathibha M. Thankamoni Amma2, Priya Chandran2, Rekha Melathuparambil Ravindran2, Remya Prakash2, Sabitha Rose Jacob2, Shameer Vadekkandiyil2, Shubin Chenayil2, Unnikrishnan Bhaskarannair2, Abhishek Gopalakrishnan Saraswthy3, Anitha Puduvail Moorkoth3, Bhagyalakshmi Mahavan Kanchana3, Biju George3, Dinesh Gopal3, Heera Hassan3, Jincy Johnson3, Kiran Raj Divakaran3, M.C. Sathya Bhama3, Megha Shaju3, Minu Abraham3, Neetha T. Ramankutty3, Pressy Sankar3, Priyanka Sajeev3, Saritha Narayanankutty3, O. Sasikumari3, Sujina Cheraparambil Muthukutty3, Thekkumkara Surendran Anish3, Vishnunath Kadavath3, Aruna Raman4, Bindu Gopalakrishnan Santhakumari4, Gayathri Ramakrishnan4, Geetha Panarkandy4, Jayakrishnan Machinery Puthanpurayil4, Mohandas Nair Karippoth4, Shameem Anathan Mohammed4, Sheeja Sugunan4, Sindhu Thekkile Gangadharan4, Anuja Ushakumari5, Chandni Radhakrishnan5, Easwaran Sreekumar5, Naveen Anaswara5, Pillaveetil Sathyadas Indu5, Reetha Kakkarakandiyil Pareri5, Sahadevan Sunija5, Sajeeth Kumar Keeriyatt Govindan5, Jaichand Johnson, Ajan Maheswaran Jaya, Abey Sushan, Raman Swathy Vaman, Lakshmi Geetha Gopalakrishnan, Arun P. Vijayalekshmi, Dinesh Kumar Harikrishnan, Sabarinathan Ramasamy, Navaneeth S. Krishna, Viswanathan V. Kollengode, Reena K. Joseph, Vinay Goyal, Rajan Khobragade, Manoj V. Murhekar
, and AME Study Group
, and AME Study Group
Table 1
Demographic distribution and clinical characteristics of all case-patients in study of amebic meningoencephalitis, Kerala state, India, 2025*
| Characteristic | rPCR |
CSF wet-mount microscopy, n = 83 | Total, N = 159 | |
|---|---|---|---|---|
| Acanthamoeba, n = 67 | Naegleria, n = 9 | |||
| Sex | ||||
| F | 28 (41.8) | 5 (55.6) | 33 (39.8) | 66 (41.5) |
| M |
39 (58.2) |
4 (44.4) |
50 (60.2) |
93 (58.5) |
| Age, y | ||||
| 0–5 | 2 (2.9) | 1 (11.1) | 2 (2.4) | 5 (3.1) |
| 6–17 | 9 (13.4) | 1 (11.1) | 26 (31.3) | 36 (22.6) |
| 18–45 | 27 (40.3) | 5 (55.6) | 24 (28.9) | 56 (35.2) |
| >45 | 29 (43.3) | 2 (22.2) | 31 (37.4) | 62 (38.9) |
| Mean (+SD) | 41.9 (20.7) | 32.1 (20.4) | 36.3 (21.7) | 38.4 (21.3) |
| Median (IQR) |
43 (29–58) |
34 (18–38) |
39 (14–55) |
40 (17–56) |
| Underlying condition | ||||
| Y | 28 (41.8) | 3 (33.3) | 31 (37.3) | 62 (39.0) |
| N |
39 (58.2) |
6 (66.7) |
52 (62.6) |
97 (61.0) |
| Underlying condition suggestive of immunocompromise | ||||
| Y | 15 (22.4) | 3 (33.3) | 23 (27.7) | 41 (25.8) |
| N |
52 (77.6) |
6 (66.6) |
60 (72.3) |
118 (74.2) |
| Clinical outcome | ||||
| Died | 17 (25.4) | 4 (44.4) | 20 (24.1) | 41 (25.8) |
| Survived |
50 (74.6) |
5 (55.6) |
63 (75.9) |
118 (74.2) |
| Days from hospital admission to death | n = 51 | n = 7 | n = 57 | n = 115 |
| Median (IQR) |
34 (25–45) |
28 (19.5–30) |
27.5 (14.2–37) |
31 (19−42) |
| Days from illness onset to hospital admission | n = 52 | n = 9 | n = 64 | n = 125 |
| Median (IQR) |
3 (0–13) |
4 (2–26) |
4 (1–11) |
4 (1–13.5) |
| Clinical manifestations | n = 64 | n = 8 | n = 76 | n = 148 |
| Fever | 32 (50.0) | 6 (75.0) | 48 (63.2) | 86 (58.1) |
| Headache | 34 (53.1) | 5 (62.5) | 44 (57.9) | 83 (56.1) |
| Vomiting | 18 (28.1) | 5 (62.5) | 31 (40.8) | 54 (36.5) |
| Seizures | 11 (17.2) | 4 (50.0) | 14 (18.4) | 29 (19.6) |
| Altered sensorium | 11 (17.2) | 1 (12.5) | 15 (19.7) | 27 (18.2) |
| Weakness in the upper limb/lower limb | 13 (20.3) | 3 (37.5) | 8 (10.5) | 24 (16.2) |
| Neck stiffness/meningeal signs | 5 (7.8) | 1 (12.5) | 15 (19.7) | 21 (14.2) |
| Myalgia/fatigue | 7 (10.9) | 0 | 13 (17.1) | 20 (13.5) |
| Diplopia | 6 (9.4) | 0 | 5 (6.6) | 11 (7.4) |
| Blurred vision | 6 (9.4) | 0 | 3 (3.9) | 9 (6.1) |
| Dizziness/vertigo | 6 (9.4) | 1 (12.5) | 2 (2.6) | 9 (6.1) |
| Loss of consciousness | 4 (6.3) | 0 | 5 (6.6) | 9 (6.1) |
| Slurred speech | 4 (6.3) | 1 (12.5) | 3 (3.9) | 8 (5.4) |
| Sensory disturbance | 7 (10.9) | 0 | 0 | 7 (4.7) |
| Chills/rigors | 3 (4.7) | 0 | 2 (2.6) | 5 (3.4) |
| Photophobia | 3 (4.7) | 0 | 2 (2.6) | 5 (3.4) |
| 6th cranial nerve palsy/upper motor neuron/lower motor neuron facial palsy | 1 (1.6) | 0 | 2 (2.6) | 3 (2.0) |
| Ptosis | 2 (3.1) | 0 | 0 | 2 (1.4) |
| Involuntary movement | 2 (3.1) | 0 | 0 | 2 (1.4) |
*Values are no. (%) except as indicated. CSF, cerebrospinal fluid; IQR, interquartile range; rPCR, real-time PCR.
1These authors contributed equally to this article.
2These authors contributed equally to this article.
3These authors contributed equally to this article.
4These authors contributed equally to this article.
5These authors contributed equally to this article.
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