**1.2 Pandemic disease**

The term pandemic is derived from Greek word "pan" meaning "all" and "demos" meaning "people". It refers to an epidemic disease which spreads among large population possibly across geographic locations or continents within a short time span [4].

Influenza, along with viral pneumonia, HIV and cholera are considered as pandemic disease and caused millions to die beside high rate of hospitalization and life threatening conditions across the globe [2]. The viral diseases like Influenza, cholera and HIV caused maximum deaths in the twenty-first century [3].

## **1.3 Vaccination**

Vaccines are available for most of the epidemic and pandemic diseases [5]. Vaccination is the most effective prevention technique to suppress the infection in healthy population [6]. However, poor and conflicted regions of Asia and Africa are deprived of these vaccines [7]. World Health Organization plays a major role in epidemic preparedness in these regions and provides extended healthcare facilities during an epidemic outbreak [8].

### **1.4 Global requirement**

Considering, the disease outbreak and its transmission is high in a poor population of developing region [9]. First line and second line antibiotics are the most effective medicines for infected subjects as the vaccines are ineffective after the infection had taken place. First line therapy includes antibiotics are the most commonly prescribed medicines to alleviate the infection process, often not responsive on several types of multi drug resistant infection [10]. Hence it is important to select a cost effective model to screen the first line antibiotics or antivirals.

#### **1.5 Fruit fly as a model organism for drug screening**

Today, we need to discover more efficacious antibiotics to fight the infectious diseases. *Drosophila melanogaster* could be a useful model organism to study the infection process and to screen an efficient drug. Due to its shorter lifespan and vast genetic similarity towards vertebrates allows conducting the drug screening experiments. It is reviewed here that *Drosophila melanogaster* was already been used to study infections caused by pandemic and epidemic diseases. But how to utilize the fruit flies to study different infectious disease and techniques to screen a potential drug candidate were not well reviewed.

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**2.5 HIV**

Drosophila melanogaster: *A Robust Tool to Study Candidate Drug against Epidemic…*

As per World Health Organization lower respiratory tract infections are caused mainly by influenza, pneumococcal pneumonia and viral pneumonia are responsible for 3 million deaths [11]. The WHO reported in 2018, 3–5 million cases of Influenza with 290,000–650,000 death cases annually [12]. As per the Global Disease burden (GDB) study report of 2015 there were around 1.5 million deaths in all age groups caused due to pneumococcal pneumonia [13]. SARS (Corona virus) causes viral pneumonia; it is epidemic to more than 30 countries with 8000 reported cases and 774 deaths during the year 2002–2003. MERS is a viral pneumonia causing infections in 688 persons and 282 deaths reported by WHO in 20

Influenza originates from *Orthomyxoviridae* family it can be differentiated into three types Influenza pandemic caused by Influenza A/B virus, seasonal Influenza and avian influenza (H5N1) [15]. Influenza virus causes upper respiratory tract infection often found to cause lower respiratory tract infection in association with bacterial co-invasion. The seasonal influenza leads to maximum hospitalization

Pneumonia is caused due to several communicable infections usually known as community acquired pneumonia (CAP), often seen in hospitalized patients. Pneumonia can be caused by bacteria like *Streptococcus pneumoniae, Haemophilus influenzae type b (Hib),* and *Chlamydia pneumoniae, Staphylococcus aureus*, *Klebsiella pneumonia* and *Mycoplasma pneumonia.* Viruses like syncytial virus, adenovirus, rhinovirus, metapneumovirus, Influenza A/B viruses, Coronaviruses, parainfluenza virus including MERS and SARS causes viral pneumonia [17]. The viral pneumonia is the influenza often associated with bacterial infection thereby caus-

Tuberculosis is caused by *Mycobacterium tuberculosis*, a gram negative faculta-

Currently HIV is the most fatal disease observed in human population across the globe. It caused maximum number of deaths around the world in the last 3 decades. As per the latest WHO report of 2019, HIV/AIDS have claimed more than 35 million deaths till date. Currently 36.9 million (31.1–43.9 million) peoples are living with HIV as of 2017 [21]. Although the rate of infection has decreased in the recent years,

tive anaerobic bacteria. In 2017 around 10 million people were infected with tuberculosis causing mycobacterium killing 1.6 million peoples across the world [19]. The current estimate of tuberculosis is not significantly different from the

resulting fatality in infants during the seasonal outbreak [16].

*DOI: http://dx.doi.org/10.5772/intechopen.90073*

countries during 2012 [14].

**2.3 Pneumonia and viral pneumonia**

ing fatality better known as superinfection [18].

still HIV remains a global burden on world economy.

**2.2 Influenza**

**2.4 Tuberculosis**

2015 WHO report [20].

**2. Epidemiology of infectious diseases**

**2.1 Lower respiratory tract infection epidemiology**

Drosophila melanogaster: *A Robust Tool to Study Candidate Drug against Epidemic… DOI: http://dx.doi.org/10.5772/intechopen.90073*
