Oropouche Fever Outbreak by SNG CK

8/9/2019 Oropouche Fever Outbreak by SNG CK

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Shakyra Goffney & Charlotte Kinsey


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Virus Laboratory Field Assistant

Nariva Swamp, Trinidad 1959

Oropouche fever is a tropical

viral infection, a zoonotic like

dengue fever

Transmitted by sloths,marsupials, primates and birds

mosquitoes from the blood one to

humans.

First discovered in 1955, in

Oropouche, Trinidad (hence thename of the virus).

It primarily occurs in the

Caribbean, Panama and the

Amazonic regions.


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OROV was first described in Brazil in 1960 when

isolated from the blood of a sloth

(Bradypustridactylus) was caught in the rain forest

during the construction of the Bel`em- Brasilia

Highway. The mosquito was later found to be the vector,

because the blood was found on it as well.

OROV is the second most frequent arboviral

disease in disease.

It causes large outbreaks in both urban centers and

rural villages in the Amazon.

About half million cases of OROV have occurred in

Brazil over the past 50 years.


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Oropouche Fever comes from the

Orthobunyavirus

Study was conducted from January 2007through November 2008 in Manaus,

Brazil

631 Patients were included in the study

Midges have become the main vector in

the transmission of the virus to man


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Midges on a Car

Biting Midge


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Comes from the

family

Bunyaviridae

Reservoir is

rodents and themain vectors are

Mosquitoes &

Ticks

Infects the CentralNervous System

and various organs

No vaccine or

antiviral drugs

Bunyaviridae Virion


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Blood samples from 631 patients

96 Well Microplates

7% Formalin buffered at pH 7.0

5% Skim Milk

Peroxidase-Conjugated Goat Anti-Human IgM

ABTS Substrate Spectrophotometer


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Blood samples were obtained from 631 patients who hadacute febrile illness for 5 days but who had negative resultsfor Malaria and Dengue

Blood samples were tested forOROV IgM

A.Albopictus cells were grown in 96 well microplates andthen infected with OROV

After 4 days the wells were fixed with 7% Formalin bufferedat pH 7.0

The microplate was blocked with 5% skim milk and the wellswere then washed and diluted serum was added to all those

infected and uninfected Wells were incubated and washed and a Peroxidase-

Conjugated Goat Anti-Human IgM was added along with theABTS substrate and cells were incubated once more

The results were read on a spectrophotometer at 405nm


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From 631 Patients: 128 IgM Antibodies to OROV

Age range 2 81 77 were female

All experienced fever 93 Headaches

90 Myalgia

74 Arthralgia

54 Rash

20 experienced hemorrhagic phenomena such as gingivalbleeding

All patients recovered without recurrence and nohospitalization


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Most cases occurred November through March during the rainyseason

Cases are usually mild and unthreatening and go undiagnosed

Patients usually mistake their ailment with a fever and often dorecover within a few days

Severe cases remain undiagnosed because of circumstancessuch as, lack of modern healthcare, lack of healthcare facilities,and lack of transportation to the few that are available

OROV is most often confused with the prevalent Malaria andDengue, hence the reason testing is initially done to rule out thetwo

Outbreak was discovered because of the surveillance for acutefebrile illness and the laboratory testing

There were probably many more cases that went undiagnosedand this only represents a small portion of the outbreak

Changes in the environment will bring more midges and moreoutbreaks in larger cities and the Western Hemisphere


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The patient sampling was good (~630 patients), especially

considering the fact that there have been approximately 500,ooo

cases of OROV over ~50 years.

However, there is nothing in the article that suggests that the

sampling was random, blind or double blind consequently leading

to its potential for bias. The researchers intentionally chose patients who had acute febrile

Illness for >5 days with negative results for malaria and dengue.

Hence, there were no comparative groups.

There was also an apparent change in some of the symptoms

from previous outbreaks of OROV. However, researchers never

gave a reason for the obvious change. However, the author did hypothesize that the changes to the

geography of the Amazon region was playing a significant part in

the public health crisis in Brazil and spread of OROV virus in the

Americas.


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Oropouche Fever Outbreak by SNG CK

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