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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. MurhekarComments to Author , and AME Study Group
Author affiliation: Government of Kerala Directorate of Health Services, Thiruvananthapuram, India (H. Sivanandan, M.A. Thali, R.M. Ravindran, S. Chenayil, U. Bhaskarannair, A.G. Saraswthy, K.R. Divakaran, M. Abraham, P. Sajeev, R.K. Pareri, A.M. Jaya, A. Sushan, R. Vaman, L.G. Gopalakrishnan, A.P. Vijayalekshmi, R.K. Joseph); Indian Council of Medical Research National Institute of Epidemiology, Chennai, India (J.W.V. Thangraj, A. Saritha, D. Gopal, M. Shaju, V. Kadavath, D.K. Harikrishnan, S. Ramasamy, N.S. Krishna, M.V. Murhekar); Government Medical College, Thiruvananthapuram (A. Bhaskar, A. Reghukumar, K.M. Amma, R. Prakash, B.M. Kanchana, H. Hassan, J. Johnson, M.C.S. Bhama, N.T. Ramankutty, S. Narayanankutty, O. Sasikumari, A. Raman, B.G. Santhakumari, S. Sugunan); Government Medical College, Kozhikode, India (A.A. Rahim, B. Vadakkayil, S. Vadekkandiyil, A.P. Moorkoth, P. Sankar, G. Ramakrishnan, G. Panarkandy, J.M. Puthanpurayil, M.N. Karippoth, S.A. Mohammed, S.K.K. Govindan); Government Medical College, Kollam, India (C. Sujatha, P.M. Thankamoni Amma); Government Medical College, Manjeri, India (P. Chandran, S.R. Jacob, B. George, S.C. Muthukutty); Kerala One Health Centre for Nipah Research and Resilience, Kozhikode (T.S. Anish); Government Medical College, Kasaragod, India (S.T. Gangadharan); Directorate of Medical Education, Kerala, India (A. Ushakumar, V.V. Kollengode); Government Medical College, Wayanad, India (C. Radhakrishnan); Institute of Advanced Virology, Thiruvananthapuram (E. Sreekumar); Kerala Centre for Disease Control and Prevention, Thiruvananthapuram (N. Anaswara); Government Medical College, Thrissur, India (P.S. Indu); State Public Health and Clinical Lab, Thiruvananthapuram (S. Sahadevan); National Health Mission, Government of Kerala, Thiruvananthapuram (V. Goyal); Health & Family Welfare, Government of Kerala, Thiruvananthapuram (R. Khobragade)

Main Article

Table 3

Risk factors associated with Acanthamoeba-caused cases by univariate conditional logistic regression analysis in study of amebic meningoencephalitis, Kerala state, India, 2025*

Risk factor No. (%) cases, n = 43 No. (%) controls, n = 129 Matched odds ratio (95% CI) p value
Occupation, painter/construction worker/farmer 5 (11.6) 13 (10.1) 1.2 (0.4–3.7) 0.768
Persons living below the poverty line
 32 (74.4)
 63 (48.8)
 2.8 (1.3–5.9)
 0.007
Use of nonchlorinated water for domestic use, household/public well, not chlorinated† 14 (50.0) 30 (32.6) 2.9 (1.1– 7.8) 0.029
Presence of fish in well† 1 (3.6) 6 (6.5) 2.9 (0.3– 31.5) 0.374
Cleaned well in previous 3 mo† 2 (7.1) 15 (16.3) 0.3 (0.0- 2.2) 0.223
Cleaned the overhead tank in previous 3 mo 16 (37.2) 60 (46.5) 0.7 (0.3–1.4) 0.275
Observed turbidity or a change in taste/smell in the water
 10 (23.3)
 21 (16.3)
 1.7 (0.7–4.5)
 0.253
Exposure to water bodies such as ponds/lakes/rivers/canals/streams for swimming or bathing or entered water body in previous 3 mo 18 (41.9) 25 (19.4) 3.6 (1.6–8.5) 0.003
History of swimming in swimming pool in previous 3 mo 1 (2.3) 0 NA NA
Reached the bottom of lakes/ponds/canals/rivers/streams during swimming/bathing/diving or experienced Tharipu 8 (18.6) 7 (5.4) 3.7 (1.3–10.8) 0.015
Practised nasal rinsing in previous 3 mo
 15 (34.9)
 37 (28.7)
 1.4 (0.6–3.2)
 0.401
Smoking‡ 8 (18.6) 21 (16.3) 1.2 (0.4–3.6) 0.686
Consumption of alcohol‡ 9 (20.9) 34 (26.4) 0.6 (0.2–1.7) 0.349
Use of nasal snuff‡
 0
4 (3.1)
 NA
 NA
Immunocompromised person§ 15 (34.9) 33 (25.6) 1.9 (0.8–4.7) 0.173
Use of steroids in previous 3 mo 6 (13.9) 12 (9.3) 1.6 (0.6–4.6) 0.390
Experienced recurrent sinusitis in previous 3 mo 6 (13.9) 10 (7.8) 2.1 (0.7–6.7) 0.214
Had maxillofacial injury or nasal surgery and exposure to ponds/lakes/canals/rivers/streams
 7 (16.3)
 6 (4.7)
 3.9 (1.2–12.4)
 0.022
Hospitalization for severe COVID-19
 2 (4.7)
 11 (8.5)
 0.5 (0.1–2.4)
 0.392
Soil/dirt contact during farming/gardening in previous 3 mo 25 (58.1) 75 (58.1) 1 (0.5–2.1) 1.000
Cleaned the air conditioner in previous 3 mo 1 (2.3) 8 (6.2) 0.4 (0.0–2.9) 0.337
Used sprinklers/hose to water plants/wash vehicles in previous 3 mo
 17 (39.5)
 51 (39.5)
 1 (0.5–2.1)
 1.000
Had any ulcers/skin lesions in previous 3 mo 17 (39.5) 15 (11.6) 4.7 (2.1–10.8) 0.001
Washed ulcers/skin lesions in ponds/lakes/rivers/canals/streams 9 (20.9) 1 (0.8) 27 (3.4–213.1) 0.002

*NA, not applicable; Tharipu, water forcefully entering the nose. †Cases, n = 28; controls, n = 92. ‡Current or past. §Diabetes, HIV, chronic kidney disease, malignancy, or immunosuppressive therapy.

Main Article

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.

Page created: July 30, 2026
Page updated: August 26, 2026
Page reviewed: August 26, 2026
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