This document discusses arthropod-borne infections like dengue fever. It provides classifications of arthropod-transmitted diseases including viral, bacterial and parasitic. It then focuses on dengue fever, describing the epidemiology, signs and symptoms, pathogenesis and phases. It discusses the dengue virus and its four serotypes. Prevention and control is through early diagnosis, treatment, community participation and mosquito control efforts like source reduction and active surveillance.

1. EPIDEMIOLOGY AND COMMUNICABLE
DISEASES
PRESENTED BY,
MRS.M.JOSEPHIN DAYANA,
TUTOR.

2. ARTHROPODINFECTIONS
• Arthropods forms a major group of disease vector with mosquitoes, flies, sand
flies ,lice, fleas , ticks and mites transmitting a huge number of diseases.
• Many such vectors are hematophagous which feed on blood at some or at all
aspects of life.
• Arthropod - A Greek Word Meaning Jointeleg(arthron:joint,pod:foot)
• It Is An Invertebrate Animal Having An Exoskeleton, A Segmented Body And
Paired Body Appendages. VECTOR • A Vector Is An Organism That Does Not
Cause Disease In Itself ,But Does Spread The Parasite To Other Life Forms.

3. CLASSIFICATION
arthropod
• Dengue
• Malaria
• filariasis
viral
• Rabies
• Yellow fever
• japanese
encephalitis
• Kyasnur forest
disease
• Chiken gunya
bacterial
• Brucellosis
• Plague
• Human
salmonellosis
• Anthrax
• leptospirosis

4. DENGUE
• Is An Acute Infectious Viral Disease, Also Known As Breakbone Fever.
• It Is AArthropod-borne (Arboviral ) Illness In Human .
• It Is Caused By Infection With 1 Of The 4 Serotypes Of Dengue Virus
(Denv1,2,3,4), Which Is A Flavivirus (A Genus Of Single-stranded Nonsegmented
Rna Viruses).
• Once Affected Persons Acquire Long-life Serotype Specific Immunity.
• Dengue Is Transmitted By Mosquitoes Of The Genus

5. • Dr Benjamin rush A Professor Of Chemistry And Medical Theory At The
UPEN, During The Philadelphia Epidemic 1779 -1780 , First Described The
Dramatic Symptoms Of Dengue As Break Bone Fever.
• A Small Percentage Of Persons Who Have Previously Been Infected By
One Dengue Serotype Develop Bleeding And Endothelial Leak Up On
Infection With Another Dengue Serotype. This Syndrome Is Termed Dengue
Hemorrhagic Fever (DHF). Also Been Termed Dengue Vasculopathy.
• Vascular Leakage In These Patients Results In Hemoconcentration And
Serious Effusions And Can Lead To Circulatory Collapse. 4
• This, IN Conjunction With Severe Hemorrhagic Complications, Can Lead
To Dengue Shock Syndrome(dss), Which Poses A Greater Fatality Risk Than
Bleeding .

6. • EPIDEMIOLOGY
• In India First Outbreak Of Dengue Was Recorded In 1812. A Double Peak Hemorrhagic Fever
Epidemic Occurred In India For The First Time In Calcutta Between July 1963 & March 1964
In New Delhi, Outbreaks Of Dengue Fever Reported INC
• 5,00,000 Cases Of DHF Require Hospitalization Each Year, Of Which A Very
Large Proportion Are Children. At Least 2.5% Of Cases Die Without Proper
Treatment.
• A Rapid Rise In Urban Populations Is Bringing Greater Numbers Of People
Into Contact With This Vector, Especially In Areas That Are Favourable For
Mosquito Breeding, E.G. Where Household Water Storage Is Common And
Where Solid Waste Disposal Services Are Inadequate.
• Increased Worldwide Distribution Of Disease Seen After World War I

7. EPIDEMIOLOGICAL TRIAD
Agent:
Aedes Egypti
Aedes Albopticus
Environment:
Rainy season
Host:
Both sexes
Adults
children

8. ETIOLOGY
• Dengue Is Transmitted By Infected Female Mosquito.
• A.Egypti Is A Primarily A Daytime Feeder. It Lives Around Human Habitation.
• Lays Eggs And Produces Larvae Preferentially In Artificial Containers . Only The
Female Aedes Mosquito Bites As It Needs The Protein In Blood To Develop Its Eggs.
• The Mosquito Becomes Infective Approximately 7 Days After It Has Bitten A
Person Carrying The Virus.

9. • This Is The Extrinsic Incubation Period, During Which Time The Virus
Replicates In The Mosquito And Reaches
• The mosquitoes Remains Infected For The Remainder Of Its Life. The Life Span
Of AAegypti Is Usually 21 Days But Ranges From 15 To 65 Days.
• The Mosquito Can Lay Eggs About 3 Times In Its Lifetime, And About 100
Eggs Are Produced Each Time.
• The Eggs Can Lie Dormant In Dry Conditions For Up To About 9 Months,
After Which They Can Hatch If Exposed To Favourable Conditions, I.E. Water
And Food.

10. • Is Primarily Transmitted By Aedes Mosquitoes, Particularly A. Aegypti.
• These Mosquitoes Usually Live Between The Latitudes Of 35° North And 35°
South Below An Elevation Of 1,000 Metres (3,300 Ft).
• They Bite Primarily During The Day.
• Other Aedes Species That Transmit The Disease Include A. Albopictus, A.
Polynesiensis And A. Scutellaris.
• Humans Are The Primary Host Of The Virus, But It Also Circulates In
Nonhumanprimates.

11. • An infection Can Be Acquired Via A Single Bite.
• A Female Mosquito That Takes A Blood Meal From A Person
Infected With Dengue Fever Becomes Itself Infected With The Virus In
The Cells Lining Its Gut.
• About 8–10 Days Later, The Virus Spreads To Other Tissues
Including The Mosquito's Salivary Glands And Is Subsequently
Released Into Its Saliva.

12. PATHOPHYSIOLOGY
• TRANSMISSION CYCLE OF DENGUE VIRUS BY THE MOSQUITO AEDES AEGYPTI
BEGINS WITH A DENGUE- INFECTED PERSON. THIS PERSON WILL HAVE VIRUS
CIRCULATING IN THE BLOOD—A VIREMIA THAT LASTS FOR ABOUT FIVE DAYS.
• DURING THE VIREMIC PERIOD, AN UNINFECTED FEMALE AEDES AEGYPTI
MOSQUITO BITES THE PERSON AND INGESTS BLOOD THAT CONTAINS DENGUE
VIRUS.
• THEN, WITHIN THE MOSQUITO, THE VIRUS REPLICATES DURING AN EXTRINSIC
INCUBATION PERIOD OF EIGHT TO TWELVE DAYS.

13. MOSQUITO LIFE CYCLE

14. TYPES OF VIRUS
• There Are Four TYPES Of The Virus, Which Are Called Serotypes,
And These Are Referred To As DENV- 1, DENV-2, DENV-3 And
DENV-4.
• All Four Serotypes Can Cause The Full Spectrum Of Disease.
• Infection With One Serotype Is Believed To Produce Lifelong
Immunity To That Serotype But Only Short Term Protection Against
The Others.

15. MECHANISM
• When A Mosquito Carrying Dengue Virus Bites A Person,
• The Virus Enters The Skin Together With The Mosquito's Saliva.
• It Binds To And Enters White Blood Cells, And Reproduces Inside The Cells While
They Move Throughout The Body
• In Severe Infection, The Virus Production Inside The Body Is Greatly Increased, And
Many More Organs (Such As The Liver And The Bone Marrow) Can Be Affected,
• And Fluid From The Bloodstream Leaks Through The Wall Of Small Blood Vessels
Into Body Cavities.
• As a Result, Less Blood Circulates In The Blood Vessels, And The Blood Pressure
Becomes So Low That It Cannot Supply Sufficient Blood To Vital Organs.
• Furthermore, Dysfunction Of The Bone Marrow Leads To Reduced Numbers Of
Platelets, Which Are Necessary For Effective Blood Clotting; This Increases The Risk
Of Bleeding, The Other Major Complication Of Dengue Fever
•

16. SIGNS AND SYMPTOMPS
• Asymptomatic Or Mild Symptoms Such As An Uncomplicated Fever( 80%)
• More Severe Illness (5%),
• In A Small Proportion It Is Life-threatening.
• The Incubation Period (Time Between Exposure And Onset Of Symptoms) Ranges From 3–14
Days, But Most Often It Is 4–7 Days.
• Symptoms Of Dengue Are
• Sudden-onset Fever,
• Headache (Typically Located Behind The Eyes),
• Muscle And Joint Pains, And A Rash.
• The Alternative Name For Dengue, "Break-bone Fever", Comes From The Associated Muscle
And Joint Pains

17. •
• Symptoms Include
• A Characteristic Skin Rash That Is Similar To Measles.
• In A Small Proportion Of Cases The Disease Develops Into The Life-
threatening Dengue Hemorrhagic Fever,
• Resulting In Bleeding, Low Levels Of Blood Platelets And Blood Plasma
Leakage, Or Into Dengue Shock Syndrome, Where Dangerously Low Blood
Pressure Occurs.

18. WARNING SIGNS
 ABDOMINAL PAIN
ONGOING VOMITING
 LIVER ENLARGEMENT
 MUCOSAL BLEEDING
 HIGH HEMATOCRIT WITH LOW PLATELETS
 LETHARGY

19. PHASES
Febrile phase
Critical phase
Recovery phase

20. FEBRILE PHASE
• High Fever, Often Over 40 °C (104 °F),biphasic In Nature Breaking And Then
Returning For One Or Two Days Generalized Pain Headache; Usually Lasts
Two To Seven Days.
• Rash Occurs In The First Or Second Day Of Symptoms As Flushed Skin,
• Or Later In The Course Of Illness (Days 4–7), As A Measles-like Rash.
• Some Petechiae
• (Small Red Spots That Do Not Disappear When The Skin Is Pressed, Which Are
Caused By Broken Capillaries) Can Appear At This Point,
• As May Some Mild Bleeding From The Mucous Membranes Of The Mouth And
Nose.

21. CRITICAL PHASE
• Critical Phase, Which Follows The Resolution Of The High Fever And Typically
Lasts One To Two Days.
• During This Phase There May Be Significant Fluid Accumulation In The
Chest And Abdominal Cavity Due To Increased Capillary Permeability And
Leakage. This Leads To Depletion Of Fluid From The Circulation And
Decreased Blood Supply To Vital Organs.[9]
• Organ Dysfunction And Severe Bleeding, Typically From The
Gastrointestinal Tract Shock (Dengue Shock Syndrome) And Hemorrhage
(Dengue Hemorrhagic Fever) Occur In Less Than 5% Of All Cases Of Dengue,
However Those Who Have Previously Been Infected With Other Serotypes Of
Dengue Virus ("Secondary Infection") Are At An Increased Risk.

22. RECOVERY PHASE
• Resorption Of The Leaked Fluid Into The Bloodstream
• This Usually Lasts Two To Three Days.
• Severe Itching And A Slow Heart Rate
• During This Stage, A Fluid Overload State May Occur;
• If It Affects The Brain, It May Cause A Reduced Level Of Consciousness Or
Seizures.

23. DENGUE HEMORRHAGIC FEVER(DHF)
• Dengue Hemorrhagic Fever Was Subdivided Further Into Grades I–IV.
• Grade I Is The Presence Only Of Easy Bruising Or A Positive Tourniquet Test In
Someone With Fever,
• Grade II Is The Presence Of Spontaneous Bleeding Into The Skin And Elsewhere,
• Grade III Is The Clinical Evidence Of Shock,
• And Grade IV Is Shock So Severe That Blood Pressure And Pulse Cannot Be
Detected.
• Grades III And IV Are Referred To As "Dengue Shock Syndrome".
•

24. LABORATORY DIAGNOSIS
• Reported Symptoms And Physical Examination;
• Low White Blood Cell Count,
• Followed By Low Platelets And Metabolic Acidosis.
• In Severe Disease, Plasma Leakage Results In Hemo concentration (As
Indicated By A Rising Hematocrit)
• Hypo albuminemia.
• Pleural Effusions Or Ascites Can Be Detected By Physical Examination When
Large But The Demonstration Of Fluid On Ultrasound May Assist In The
Early Identification Of Dengue Shock Syndrome.

25. PREVENTION ANDCONTROL
Earlydiagnosisand
treatment
Communityparticipation
Mosquitocontrol
Activesurveilance

26. ACTIVE SURVEILLANCE
 It Is An important component of a dengue prevention programme.
The goal should be to provide an early warning or predictive
capability for epidemic transmission, that emergency mosquito
control programme can be initiated
Hospital used an sentinel sites should includes all those upon the
patients who have severe infectious diseases in the community

27. MOSQUITO CONTROL
 Prevention And Control Depends On The Control Of The mosquito
vector in and around home, where most transmission occurs.
 The most effective way to control the mosquito that transmits
dengue is larval source reduction
 Elimination or cleaning of water holding containers that serves as
the larval habit in domestic environment

28. COMMUNITY PARTICIPATION
 Now a days , emphasis is on the community based approaches.
Prevention programmes require extensive health education to
achieve community participation.

29. PREVENTION OF DENGUE IN TRAVELLERS
 Staying In Screened or air conditioned room
Spraying the rooms with aerosol bound insecticides to kill adult mosquitoes
indoor.
 using a repellent containing DEET( dimethyl meta-toluamide) on exposed skin
 wearing protective clothing (long sleeved clothing and pants)
Use mosquito net to prevent you from mosquito bites.

30. NURSING MANAGEMENT
 Thorough assessment of the patient, provide adequate bed rest
Continuous watch on vital signs
Hydrate with adequate fluids like milk, fruit juices and ORS
Tepid sponging when applicable
Administered antipyretics as prescribed, should not exceed more
than 4g per day
 Eliminate the mosquito breeding place and use mosquito net to
prevent mosquito bite