Assignment- blood and age determination

[Patchara Sriwichai]

1. Please send me (via mail: patchara.sri@mahidol.ac.th) the picture of “ovary” that you dissect from the mosquitoes and describe in the group discussion; character, shape, how to collect. (50%)

2. How important of blood determination and mosquito parity rate? (50%)
– Methods of determination
– Application of these 2 parameters

[TIPAWAN AMMARIT]

Hi there~ I’m Tipawan ammarit, student ID 6438166.

First of all, I already sent mosquito ovary dissection that I dissected it by myself via mail.
1. So I’m gonna describe character, shape, how to collect of parous ovary.
– Character: Tracheoles in ovary were expanded longer than tracheoles of nulliparous ovary that tightly rolled called a ‘skein’shown inside the ovaries.
– Shape: Parous and nulliparous ovaries have 2 sides oval-shaped ovaries at abdomen segments number 7 and 8.
– How to collect: used ether to temporarily sleep mosquitoes. Thus pick one and put down under stereomicroscope then put the legs and wing out by micro forceps for easily dissection. After that, arranged the mosquito head to your inconvenient-hand side and used that hand to hold minus needle to softly fix at thorax part for stay still for while then used another another hand to hold another minus needle to softly press and pull at abdomen segment number 7 out and then you will see 2 loops of oval-shaped ovaries as shown in my picture. Then if you want to see more details about tracheoles inside ovaries for determine age of mosquitoes, you must separated only mosquito ovaries and put on the glass slide, let’s them dry, and look under stereoscope.

2. How important of blood determination and mosquito parity rate?
– these 2 methods are important to surveillance and monitoring of vector’s capable ability such as can show about the proportion between anthropophilic and zoophic patterns for classify the main host of mosquitoes, and for voctor control.
– Methods of determination: can used various methods such as precipitin test (antigen bind with antibody, less specificity), enzyme-linked immunosorbent assay(ELISA, more specificity), multiplex PCR/DNA barcode, microsatellites, and mass spectrometry to determine blood in mosquito. Moreover, used the the presence and absence of tracheolar skeins at ovaries of female mosquitoes dissection to study of parity rate.
– Application of these 2 parameters: for mosquito parity rate used dissection method for counting the number of ovarioles to determine the age structure of the population (can predict opportunity to spread the vector borne disease means vector capacity). Next, for blood determination used to identify pathogens in blood meals from mosquito bitting to monitoring the vector capacity.

Thank you very much.

[VANHEUANG PHOMMADEECHACK]

Hello everyone!
Please find my opinion as below:
1. I have sent pictures of the mosquito ovaries to Ajan via email.
The mosquito ovary can be used to evaluate the age of the mosquito and also can be used to determine whether this female mosquito has laid eggs before or not. We can dissect the ovary of the mosquito (fed or non-feeding) under a stereomicroscope by using minute needles. I start with anesthetizing a female mosquito by using Ether and then remove their legs and wing to make sure that it can’t move. Put mosquito on the prepared slide with normal saline and prepare another slide for transferring the ovary. Separate mosquito in to 2 part head+thorax and abdomen using minute needle, lay the needle across the 7th abdomen segment and slowly detach the terminalia, transfer ovaries to prepared slide, cover by cover slip, leave it dry and observe under the microscope.
The term Parity is the term that use to determine the age of wildlife including mosquitoes. There are parous and nulliparous that describe the parity status of the female mosquito as below:
1.1 Parous means the female mosquito that has taken the blood meal and has laid egg before. We can see that the tracheole is distributed. Sometimes, we also can see the egg-containing in the ovaries.
1.2 Nulliparous is the term that us to describe the female mosquitoes that never lay egg or feeding. We can see that the tracheole is tightly coiled call “skein” show inside the circle.

2. The termination of blood source and mosquito parity rate are important in role of vector capacity, because we will know the host preference, host-feeding pattern and proportion, and we also know the longevity of the mosquitoes from age determination of mosquito to apply in the monitoring of disease transmission and vector control.
– The method for blood source determination can be done by precipitin test, ELISA, multiplex PCR or DNA barcode, Microsatellites and Mass spectrometry.
– The method for age determination can be done by examining the morphology of ovaries or the structure of the tracheal system. Each of dilatation represents one gonotrophic cycle, so we can use this tool for estimating the age of the mosquito.
– Application of blood determination and mosquito parity rate is for surveillance and monitoring of vector capacity.
The application that use for age determination can be done by the multiplication between Number dialatation and days of gonotrophic cycle (Age grading= Number dialatation x days of gonotrophic cycle).

Thank you very much and happy to hear feedback and discuss with ajan and friends.

Cheers!
Vanheuang Phommadeechack. Student ID: 6436660

[RATTANALAK JITTUNGDEE]

Rattanalak Jittungdee
student ID : 6438165

1. Describe in the group discussion; character, shape, how to collect.
1.1 Character of ovary dissection from the mosquitoes
– Parous ovary: the tracheoles are released because the mosquitoes that have been taking a blood meal and oviposited before.
– Nulliparous ovary: can see the many coiled tracheoles inside the ovary
1.2 Shape of the ovary
– can see the two oval lobes of the ovary when you pull the segments 7th and 8th out.
1.3 How to collect?
– Anesthetize mosquitoes with ether.
– Pull out the legs and wings of the mosquito.
– Use a needle to hold the mosquito with one hand.
– Use another needle to gently pull out the 7th and 8th segments of the mosquito together.
– You will see 2 bunches of ovaries attached to it.
– Then cut the ovaries out and place them on the prepared slides.
– Wait for it to dry and then observe it with a microscope.

2. How important of blood determination and mosquito parity rate?
: if we know the source of blood in the vector we can determine the relation between host and mosquitoes, host preference, host-feeding pattern, and proportion in mosquitoes. and parity rate causes us to know that areas have more or less breeding places that are connected with the transmission rate. also counting the number of ovarioles from captured mosquitoes can determine the age structure of the population.
– Methods of determination
: – The methods to determine the blood source in the mosquito can use in many ways including
• the precipitin test
• enzyme-linked immunosorbent assay (ELISA)
• multiplex PCR/DNA barcode
• Microsatellites
• Mass spectrometry
– The method of age determination including
• Parity rate in ovary dissection that each dilatation represents one gonotrophic cycle.
• Molecular markers: detect some proteins that increase or decrease after being oviposited of mosquitoes.
– Application of these 2 parameters
: can apply to surveillance and monitoring to determine vector capacity in those areas. cause to know that transmission of disease is more or less and to control the vector as soon as possible. For example, the age of female mosquitoes is determined by multiplying the number of dilatation of tracheoles in the ovary and the number of days of the gonotrophic cycle. also, the blood determination can find a host-feeding pattern and host preference in the vector.

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