Kyasanur Forest Disease: Outbreaks, Surveillance & Control
Kyasanur Forest Disease (KFD) is a re-emerging zoonotic tick borne arboviral disease affecting monkeys and
man. This disease was first discovered in 1957 from Kyasanur forest area, Shimoga district of Karnataka state
following monkey deaths and human cases. The common sign and symptoms of KFD are fever, myalgia, diarrhoea,
cough, hepatomegaly, splenomegaly, epistaxis later leading to oral and intestinal haemorrhages and meningoencephalitis.
The disease in man is often fatal unless diagnosed early and treated symptomatically. The case fatality
rate (CFR) is about 2 to 10%. KFD is a viral hemorrhagic fever caused by flavi virus, which is immunologically related
to Russian Spring Summer Encephalitis (RSSE) virus.
The lxodid ticks of the genera Haemaphysalis are the vectors of the disease and a number of forest dwelling
small mammals like rodents, shrews, an insectivorous bat and many birds maintain the natural enzootic cycle of
the virus in the forest ecosystem. The wild primates black faced langurs (Semnopithecus entellus) and red faced
bonnet monkeys (Macaca radiata) get the virus infection by tick bite and they act as amplifying hosts and also
susceptible to the infection. The monkey death area are treated as ?hot spots? due to dropping of infected ticks
from their body with high titers of virus. Human beings get the infection by tick bites while visiting these areas
owing to forest related occupation. High mortality of monkeys (Epizootics) are observed during the months of
December to June which is coinciding with the seasonal activity of nymphal stages of Haemaphysalis ticks.
KFD is a seasonal disease mainly reported during early and peak summer months and other forest fringed
areas during the transmission period. In the areas of reporting monkey deaths, health education to the community
is essential and people should be advised to avoid venturing in the forest. Persons who need to visit the forest for
occupational purpose should cover their body with thick clothes and topical application of tick repellants like DMP
oil, in order to avoid tick bites. All monkey deaths in the forest and adjoining villages should be reported to the local
health authorities for further investigations and to undertake insecticidal treatment of the floor area covering a
radius of 50 metre radius of the hot spot.
KFD is endemic in Shimoga district, a primitive sylvan territory in Western Ghats due to
deforestation, encroachment and human colonization of the above area. The disease was restricted to above area
till 1971, subsequently moved to Chikkamagalore, Uttara Kannada, Dakshina Kannada and Udupi districts and later
in 2012 to Chamarajanagar district. In 2013, KFD was detected in autopsy of dead monkeys in Nilgiris district of
Tamil Nadu state. More recently monkey deaths and human cases were reported from three neighbouring States
bordering Karnataka viz., Wayanad and Malappuram districts of Kerala (2014 ? 15), North Goa district of Goa State
(2015-16) Sindhudurg district of Maharashtra and recently in 2016 in Belagavi district of Karnataka State (2016). It
is evident that, the KFD is centripetally spreading to newer territories. The probable reasons are due to interplay of
a complexity of factors related to deforestation and human settlement in forest biotopes. Improved surveillance,
enhanced diagnosed facilities and timely undertaking of appropriate disease specific control measures are very much needed for the successful containment of the disease in endemic and newer areas.
Outbreak reporting under IDSP: KFD outbreaks have also been reported under IDSP. The details of the KFD outbreaks reported by States/districts are as under. However number of cases and deaths are not final, but as reported by states at the initiation of outbreak.
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KFD Outbreak Investigation Report from District Sindhudurg, Maharashtra By
Dr N.Balakrishnan Joint Director NCDC Bangalore, Dr. Sanket Kulkarni Asstt. Director, IDSP
& Dr. Harish Shukla EIS officer NCDC.
Background:-
? Two people were admitted with complaints of fever with headache, body ache and Myalgia and reported to a
Hospital in Goa. As the KFD outbreak was ongoing in Goa, both were tested for KFD. Thus the first case of KFD
was detected and was cross notified to District Sindhudurg. Further investigations of the 28 cases with similar
complaints in Ker Village under PHC Sateli Bhedashi was done by NIV Pune.
? Out of 28 samples sent to NIV Pune 18 samples tested positive for KFD by IgM Elisa. On further investigation
cases with similar complaints were also reported in nearby villages like Zolambe, Asaniye, and Kolzar. Samples
from these villages were also tested and found that 5 from Asaniye, 4 from Zolambe and 3 from Kolzar were also
positive by IgM ELISA. Hence this was confirmed to be an outbreak of KFD and this was communicated to IDSP,
New Delhi on 23.2.2016 and asked for assistance to investigate.
Date of Investigation: 29.02.2016 to 03.03.2016
Central team was sent to investigate the outbreak which started on 29.02.2016.
Details of Investigation:
The team members visited the area on 29.02.2016 along with the state officials and support staff. Initially
the medical officer from PHC Bhedashi was met and the area involved with the outbreak was discussed. The details
of the outbreak including line lists, no of monkey deaths and area of monkey deaths was collected.
Objectives
1. To determine the magnitude of the outbreak.
2. To determine epidemiological characteristics of the outbreak.
3. To determine risk factors associated with this outbreak
Methodology:
On discussion with state health authorities about the outbreak and after formulating and reviewing the line
list of cases as well as interacting with patients in the line list a case definition was prepared.
Case Definition:
Clinical Case: A person residing in an area under PHC SateliBhedashi or PHC Talkat with a presentation of
fever with headache, body ache and myalgia with or without haemorrhagic or neurological manifestations
from 09/01/2016.
Confirmed Case: A clinical case positive by RT-PCR or IgM ELISA.
Line list of cases was prepared and analysed for Time, Place & person.
Result
Investigation findings:
Confirmation of the outbreak: From 09th Jan
2016 to 03rd Mar 2016, a total of 54 samples
were sent for testing at NIV Pune of which 29
samples were tested positive (53.7%) for
KFD. As the disease is being diagnosed for the
first time in the state, no cases have occurred
in last five years which confirms the
existence of an outbreak. But 8 samples were
tested positive for IgG antibodies which
confirms the past infection in the area but
was not diagnosed.
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http://idsp.nic.in/showfile.php?lid=3785
