Effects on climate on

Transovarial Infection Rate of Dengue Virus in Aedes aegypti (Diptera: Culicidae) Mosquitoes

The 10th CRISU-CUPT International Conference

Trilateral Scietific meeting Climate change: Observation, Analysis and Health

Tri Baskoro Tunggul Satoto

tribaskorots2@gmail.com; tribaskoro@ugm.ac.id Entomology Division ,

Faculty Of Medicine, Gadjah Mada University, Indonesia

INTRODUCTION

Indonesia is one of the DHF endemic countries of SEA

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CF

R (

%)

IR (

Ka

su

s P

ER

10

0.0

00

pe

nd

ud

uk

)

TAHUN

Trend Angka Kesakitan & Angka Kematian DBD di Indonesia1968-2014

IR

CFR

Case fatality Rate and Incident Rate Dengue Haemorhagic Fever

The History of DHF in Indonesia

First DHF case was found in 1967 only in 7 province

Currently is developed in all 34 province

The Highest IR in South-East Asia

Dengue vector

Anthrophophilic endophagic

Egg Adult 7-9 days

Habitat Larva pH 5.8-8.6

Day biting 7-10 am;15-17pm

Multiple biting

Laying eggs in clear water, on vertically wall

Aedes aegypti

ADULT

EGGS

LARVA

PUPA

Aedes aegypti life cycle

Optimize of community in Larva Source reduction activity utilization, in school, communities, offices, public places and

also religious worship places

Optimize of DHF surveillance system as EWARS, which consist of:

Periodic larva monitoring

Monitoring number of DHF cases

Increase the promotion regarding Larva Source reduction management DHF cases

Indonesian Goverment Strategies

Dengue control

Effective usage and, ENVIROMENTLY SAFE is priority;

which is by using 3M + FISH USAGE (Drain, Cover,

Bury, and FISH USAGE)

Larviside is suggested only on water container that

is not possible for 3M Plus.

Fogging in outbreak areas

Aedes mosquito breeding (Argentina)1:

Highest abundance mean temp. 20C, accumulated rainfall (150 mm)

Decline egg laying monthly mean temperature

Association between weather and climate on

VBDs

IPCC AR5, 2013

Hii et al., 2012

Association between dengue cases, temperature and rainfall

Vector and Host Seasonality

Vector-borne zoonoses mostly maintained by wildlife

Humans are irrelevant to their ecology

Vectors and their hosts are subject to seasonal variations that are climate related (e.g., temperature) and climate

independent (e.g., day-length)

Seasonal variations affect abundance and demographic processes of both vectors and hosts

Vector seasonality due to temperature affects development and activity transmission

Host demographic processes (reproduction, birth and mortality rates), affected directly by weather and

indirectly by resource availability VBD epidemiology

Global warming intensify El Nio

Several studies found relationships between dengue epidemics and ENSO (El Nio Southern Oscillation)

Drought conditions: increase water storage around houses elevated Aedes aegypti populations

Enhanced breeding opportunities when rainfall accumulates following drought (Kuno et al., 1995)

ENSO= global scale

pattern of climate

variation accounting for

up to 40% of temperature

and rainfall variation in

Pacific

Hales et al., 1999;

Tipayamongkholgul et al, 2009

Example of Weather Effects: El Nio

Mourya et al. (2001) demonstrated clearly in their lab experiments that DENV-2 virus could be horizontally transmitted by Ae. aegypti mosquito after transovarial transmission.

Joushi et al. (2003) showed persistence of DENV-3 virus through transovarial transmission passage in successive generations of Ae. aegypti mosquitoes; this evidence suggests that Ae. aegypti may play an important role in maintenance of DEN-3 virus in nature, and that mosquitoes may act as reservoirs of the DENV.

Mardihusodo et al. (2007) Occurrences of DENV transovarial transmissions tend to increase as found out in Ae. aegypti in

many occasions, either in laboratory or field studies. It seems

that DENV transovarial transmission to be increasing its role in

forthcoming emergence of DHF cases.Such phenomenon might

be occurring in 12 DHF endemic foci in Yogyakarta under

studies.

Transovarial studies

(Beaty, et al.,

1996)

Objectives

To identify the environmental changes influence (air temperature and air humidity) and the length of time Ae. aegypti mosquito eggs storage towards the transovarial Infection rate (TIR) virus DEN.

Material and methods

DEN-2 virus infection per oral on mosquito regarding membrane feeding method

Ae. aegypti mosquito egg collection per individual

Adult Ae. aegypti mosquito head above glass prepared for

head squash

Head squash Ae. aegypti mosquito after coloring and ready to be examined

Microscopic virus DEN-2 on head squash adult Ae.aegypti

A (Positive) B (Negative)

C (Positive Control) D (Negative Control)

A (Positive) B (Negative)

C (Positive Control) D (Negative Control)

F0 Generation

F1 Generation

TABLE. Antigen DEN-2 on head squash main mosquito (Fo) and its progeny on

imago (F1) stage. Incubation time is 13 days based on immunocytochemistry

SBPC menthod using monoclonal antibody DSSC7 as a primer antibody

Mosquito

generation

Mosquito examined

group

Antigen Virus DEN-2 Infection

Rate

(%) Positive Negative Total

number

F0

Infected with virus

DEN-2 56 4 60 93,3

Uninfected with virus

DEN 0 30 30 0

F1

Infected with virus

DEN-2 74 16 90 82,2

Uninfected with virus

DEN 0 30 30 0

Positive Control *) 27 3 30 90,0

Negative Control **) 0 30 30 0

IV. RESULT AND DISCUSSION Result and Discussion

Temperature and air humidity for Ae. aegypti egg storage has an affect toward ITR virus DEN-2

Conclusions

Climate change will affect the distribution and incidence of VBD globally

Impacts will vary from region to region

Current evidence suggests impacts on some diseases may already be occurring

Risk assessments constrained by complex transmission cycles and multiple determinants

Non-climatic factors remain important determinants of risk

Impacts may include unanticipated emergence of new pathogens

Future research collaboration

Study is needed to identify the virulence of dengue virus on mosquito in different temperature which can be

infected on human is beneficial for early warning system

Percentage of infected transovarial rate (ITR) DEN-2

in different temperature and humidity

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T1,RH1 T2,RH2 T3,RH3

Types of treatment

ITR

(%

)

7 Days 14 Days

Colonized (+)

vir DEN-2

(Lab)

Frame works

Egg

collection

(Ovitrap)

K2

K3

K4

K1

Adult

mosquito

(age 7 days

and 14 days)

Virus detection

Method IISBC

Transovarial Infection Rate (ITR)

K.T1

K.T2

K.T3

K.T1

K.T2

K.T3

K.T1

K.T3

K.T1

K.T2

K.T3

K.T2

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Average temperature and air humdity in the morning and afternoon based on

groups with 14 days treatment

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Treatment

Temperatur (0C) 26.1 23.8 33.8 27.2 24.8 34.5

Humidity (%) 84.8 90.3 71.1 81.9 88.2 70

T1,RH1 T2,RH2 T3,RH3 T1,RH1 T2,RH2 T3,RH3

Morning Afternoon