Vanutsarin Khongsrisak

[Vanutsarin Khongsrisak]

From previous reports (https://academic.oup.com/jme/article-abstract/19/1/98/2219935?redirectedFrom=fulltext&login=false)
“During the monsoon malaria-transmission season of 1978, infrequent feeding on humans coupled with reduced anopheline life expectancy contributed to low estimates of the malaria vectorial capacity for Anopheles culicifacie and Anopheles stephensi”

Vectorial capacity calculation

VC = ma^(2)p^(n)/-In(p) —Equation of vectorial capacity
VC = (HB*a)(e^(-n/E)E) —Applied equation from this report
HB(t); the human biting rate in females per human per night.
a; anthropophagic index
n; duration of gonotrophic cycle in days
E; Life expectancy

Ex. Estimated vectorial capacity for P.vivax and P.falciparum of An.culicifacies in December.
for P.v.
VC = (HB*a)(e^(-n/E)E)
; from data table HB=0.102, a=0.022, n=27.42, E=5.40
VC = (HB*a)(e^(-n/E)E)
= (0.102)*(0.022)*(e^(-27.42/5.40))*(5.40)
= 0.000075538 = 7.55*10^(-5)
for P.f.
VC = (HB*a)(e^(-n/E)E)
; from data table n=47.64
VC = (HB*a)(e^(-n/E)E)
= (0.102)*(0.022)*(e^(-47.64/5.40))*(5.40)
= 0.000075538 = 1.79*10^(-6)

Ex. Estimated vectorial capacity for P.vivax and P.falciparum of An.stephensi
for P.v. in December.
VC = (HB*a)(e^(-n/E)E)
; from data table HB=0.135, a=0.016, n=27.42, E=3.75
VC = (HB*a)(e^(-n/E)E)
= (0.135)*(0.016)*(e^(-27.42/3.75))*(3.75)
= 5.41*10^(-6)
for P.f.
VC = (HB*a)(e^(-n/E)E)
= (0.135)*(0.016)*(e^(-47.64/3.75))*(3.75)
= 2.46*10^(-8)

[Vanutsarin Khongsrisak]

1. What is the benefit of cell culture?
Cell culture is one of the techniques to study cell proliferation and understand their model system. This technique is widely used for investigating the cell under controlled conditions, generally outside of their neutral environment like when we needed to research virus biology, vaccine development, the role of genes in disease and health, and biopharmaceuticals. It’s used as a tool for many fields including;
– Models and systems in health and disease: study the route of interaction and infection route between cells and pathogens.
– Drug development and drug testing: Most of them are used to detect the efficacy or quality of drugs to find suitable chemicals compound before treating diseases, including screening novel chemicals and cosmetic products.
– Manufacturing of biopharmaceuticals: A large-scale production of antibiotics, enzymes, therapeutic monoclonal antibodies, therapeutic hormone formulations, etc.
– Other: Vaccine Production, Tissue Regeneration and Transplantation, Genetic Engineering, and Gene Therapy.

2. How to measure the virus concentration using the cell culture technique?
The measurement of virus concentration can be measured in two methods by using cell culture techniques, including plaque assay and TCID50 assay
Plaque assay
The plaque assay relies on determining the number of plaque-forming units (PFU) created in a monolayer of virus-infected cells. The assay requires the cultured susceptible cell to infect with the virus that interest. Bring the cultured cell that is fully growing on the well plate and add the serial dilution of the virus, incubated at 37oC in CO2 for around 3-4 days. After staining with 1% crystal violet in ethanol 3-5 drops, stand for a few minutes and wash the well plates to observe plaque formation. And calculate by using the equation to determine the virus concentration in mL.
50% Tissue Culture Infectious Dose (TCID50) assays, the use for the quantification of the virus. The process will be like the plaque by preparing serial dilutions of the virus and adding to the host cell, but they do not form the plaque. After the cell that contains the virus is incubated, we will calculate the percentage of dead cells from a cell viability assay by using a plate reader or observing under the microscope. The result showed a 50% infection dose per mL.

Vanutsarin Khongsrisak ID:6536456

[Vanutsarin Khongsrisak]

Malaria is caused by Plasmodium parasites, which are transmitted through the bites of infected female Anopheles mosquitoes. On the other hand, culicine mosquitoes(Aedes, Culex, and Mansonia mosquito) can be important vectors for human pathogens and feed on humans like the Anopheles mosquito. For this reason, it raises the question of Why Aedes aegypti is not a malaria vector. The previous report showed that the plasmodium parasite does not successfully develop and transmit in Aedes or culicine mosquitoes. Even found an Aedes mosquito in the Malaria endemic area. The fact that Aedes mosquitoes are not able to pass the Plasmodium parasite like Anopheles mosquitoes. Because the factors and immune response in the Aedes mosquito (culicine mosquito) are too strong and play a crucial role to makes the Plasmodium parasites have poor adaptation to new disease vectors(factors beneficial to the host). In addition, the Aedes immune response can not influence the plasmodium parasite to survive in their body(the gut) and prevent the transmission of the human-infectious Plasmodium parasite.

Vanutsarin Khongsrisak ID: 6536456

[Vanutsarin Khongsrisak]

The transmission mechanism of pathogens by mosquitoes consists of three patterns. The first is eggs. Infected female mosquitoes can spread the pathogen through eggs. The pathogen emerges in the embryo or on the egg surface. Both male and female mosquitoes can become infected. We call this Vertical transmission. The second is a bite. An infected mosquito bites a susceptible vertebrate host after an intrinsic incubation period host becomes an infected host. When the susceptible mosquito feeds on the blood of the infected host that carries the pathogen after an extrinsic incubation period the mosquito becomes infected. We call this Horizontal Transmission. And the last is mate. Both of them can be infected(male and female mosquitoes) if one of them has the pathogen in itself while the mating process. We call this Venereal Transmission.

Vanutsarin Khongsrisak ID: 6536456

[Vanutsarin Khongsrisak]

Sand flies are small insects in Order Diptera, Suborder Nematocera, Family Psychodidae, and Subfamily Phlebotominae. They prefer to live in tropical, subtropics, and warm mainland regions. The sandfly’s life cycle begins with eggs, larvae, pupa, and adults. The general characteristics of the adult sand fly are small hairy flies. It has large dark eyes, long slender legs (stilts-like), and long antennae with 16 segments. We can see that when the sandfly rests, They have a vertical “V” shape over their back. They have sucking mouthparts to pierce the skin and take the blood meal of mammals, reptiles, and birds(only females). Sandfly is known as the main vector of Leishmaniasis(Leishmania spp.). They can transmit the pathogen while feeding on a blood meal. The sandfly feeds on the blood of an infected human host, carrying the pathogen which develops inside the sandfly body and becomes infected sandflies that contain the infection stage of the pathogen. The infected sandfly then feeds on the blood of the new human host and transmits the pathogen into the new human host. This brings bad luck to hosts who are bitten by infected sandflies and eventually become infected.

VANUTSARIN KHONGSRISAK ID:6536456

[Vanutsarin Khongsrisak]

1. How the mosquito can transmit the pathogen?
The transmission of the pathogen by mosquito vectors can occur in 3 ways during the activity or life cycle of the mosquito such as lay eggs, biting, and mating. The first one is Vertical Transmission, which occurs when the female mosquito passes the pathogen to its embryo. And made the next generation of mosquitoes get infected in the male and female mosquitoes. The second is Horizontal transmission, which occurs following the infection of a human or animal host by the bite of an infected mosquito. After intrinsic incubation, the human or animal host will become a viraemic host, and wait for a new mosquito to take a blood meal to lead to an infected mosquito. The last one is Venereal transmission. It occurs when an infected male mosquito that infect by vertical transmission, mating with a female mosquito. The pathogen can be directly transmitted to female mosquitoes. Both males and females can be infected.
2. What tool and how to determine malaria transmission?
Malaria transmission has 6 main parameters that use to determine coupled with vector surveillance which is the tool to identify the response of the vector in each specific place and time or the pattern of the vector transmission :
Abundance; the number of mosquitoes (A large number of mosquitoes increases the chances of spreading the disease)
Host-feeding pattern and proportion; the mosquito prefers to bite on animals or humans
Longevity; to know how long the vector’s life cycle
Reproductive capacity; the reproduction rate of the population of mosquito vector or the number of generation
Distribution; the distribution of mosquitoes at that time and place
Vector competence; the capacity of the mosquito can transfer the parasite to another host and the susceptibility of vector

Name: Vanutsarin Khongsrisak ID: 6536456

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