Use of rabbit and sheep in microbiological laboratory.

 

      Use of rabbit and sheep in microbiological laboratory.

 Use of Rabbit

            1. To obtain HIB (Ambo ccptor) for WR test.

            2. To perform ASO-  titre (Rabbit RBC+ Serum+ Streptolysim→Incubated→Read                             haemolysis  for Aso titre).

              3. To perform coagulase test suspension of organism+ Rabbit plasma→ clumping means                 coagulase positive.

               4. Pathogenicity test for H. influenza.

               5. Isolation of Borellia in naguchi medium.

               6. Culture media for leptospira.

               7. Mentaining treponema pallidum by serial passage in Rabbit.

                8. Animal inoculation for cultivation of herpes simplex.

            9. Rabbit brain used for thromboplastin for prothrombin time.

Use of sheep

          1. Preparation of haemolytic system for WR.

          2. Paul- Bunnel reaction.

          3. Rose- waller test.

           4. Preparation of Hiss serum water, blood agar and chocolate agar.

           5. Detection of Rhino virus by haem agglutination technique.

           6. Prep of viral vaccine against rabies.

What is AIDS, & Diagnosis of AIDS in laboratory

What is AIDS,  & Diagnosis of AIDS in laboratory

Aids stands for Acquired Immuno deficiency Syndrome. It is the end stage of disease                                        representing the breakdown of immune defence mechanism, leaving the patient pray to                        opportunistic infection and malignancies the illness progress and death ensues in month to year.                       Due to most system affected, patient present with various complain.

        (a). Increasing dry cough, dyspnea and fever.

        (b). Gastrointestinal system in GIT it causes thrush, Gingivitis, Dysphasic chronic Colitis.

        (c). Lymphoma of CNS.

Ø  Causative organism in HIV(HUMAN IMMUNO DEFICIENCY) diagnosis of AIDS in laboratory.

(a). Screening test: ELISA test for HIV and HIV card test are done to screen out the patient. If it is                                                                           found positive then it should be conform by specific test.

(b). Specific test for HIV:-

(i). Antigen detection: The virus antigen may be detectable in blood after about 2 weeks.

(ii). PCR: It stands for polymerase chain reaction. It is most sensitive and specific test. It is used                     in two forms DNA   PCR & RNA   PCR

(iii). Antibody detection: It is done by serological method. It may take 2-8 weeks to months for                                                      antibody to appear after infection.

(iv). Wesion biot test: It is very useful confirmatory test.

(c). Immunological test:-

(i). Total leucocyte and Lymphocyle count to demonstrate leucopaenia and lumphocyte count us                  n    usually below 2000/ml.

 

(iii). Cell count will be usually < 2000/ml

       Platelets count will show throbocytopaenia

       Raised IgG and IgA level

       Lymphnode biopsy showing abnormalities

Post-mortem of Lab animals

 

1.       Post-mortem of Lab animals

Post mortem is scientific examination of tissues and organs of a dead animal or cadaver determine cause of death, extent of lesion and nature of illness. This is also called atopsy. Following changes should be noted during postmortem examination.

              1. Hypostatic congestion

             2. Rigor mortis

             3. Decomposition and soft ening of tissue.

             4. Condition of organs, viscera, bones and joints.

Ø  Post mortem is also done to recover organs in which experimental material has been injected.

Ø  Post mortem should perform in safety cabinot.

Ø  Materials removed from post mortem should be autoclaved or incinerated.

Ø  Post mortem should be under taken as soon after animals death to avoid bacterial and viral infections.

Ø  Carcasses of animals should be placed in 1% cresol and Later disposed off by buring after post mortem.

                 Post mortem report is written in following manner.

A. Atopsy number

B. Name of owner of animal

C. History of death- Died/killed/Experimented

D. Species/sex/breed/colour/age and clinical diognsis illness.

E. Muscutar rigidity found in muscles along with condition of nutritional states, skin, hair and condition of organs.

F. Description of material collected during post mortem

G. Result of Laboratory Experiment

H. Cause of death/ Etiological diagnosls.

Study of FNAC

                                                             FNAC

FNAC stands for “fine needle Aspiration cytology”. It is a method of cytopathoLogical examination.

          Modalities of FNAC:

Ø  Direct vision FNAC for superficial masses.

Ø  Computed tomography guided FNAC for deep seated masses. Such as intraabdominal organs, pelvic organs or masses in the brain substances.

         Method of FNAC performance:- 20ml of plastic disposable syringe with 21 gauge. Fine needle of variable length are used for aspiration.

                                    Tumour mass is fixed with one hand and with other hand aspiration is carried out. When needle enters tumour, plunger of syring is retracted to create a vaccum in barrel. The needle is moved to and fro for sevral times (10-15 times in different directions 3-4 directions.) The plunger is kept retracted during needle is drawn. Outside the tumour mass plunger is released, needle is disconnected and contents of barrel is discharged over a slide. Smear is prepared by pressing it with another slide and with drawing it in close contact. Smear is immediately fixed in 90% ethyl alcohol for 3-5 minutes. The smear is now ready for staining.

        Method of staining:

Ø  Wet fixed smear is stained by Papanicolauou method of H & E method.

Ø  Air dried smear is stained by May Grunewald – giemsa stain or Leishman stain.

Method of FNAC performance:- 20ml of plastic disposable syringe with 21 gauge. Fine needle of variable length are used for aspiration.

                                Tumour mass is fixed with one hand and with other hand aspiration is carred out. When needle enters tumour, plunger of syringe is retracted to create a vaccume in barrel. The needle is moved to and fro for sevral times (10-15)times in different directions (3-4 directions). The plunger is kept retracted during needle is drawn. Outside the tumour mass plunger is released, needle is disconnectedand contents of barrel is discharged over a slide. Smear is prepared by pressing it with another slide and with drawing it in close contact. Smear is immediately fixed in 90% ethyl alcohol for 3-5 minutes, The smear is now ready for staining.

Method of staining

1)      Wet fixed smear is stained by papanicolauou method of H&E method.

2)      Air dried smear is stained by may grunwald-Giemsa stain or Leishman stain.

Advantage of FNAC

1)      Aspiration is done by cytopathologiest himself who can interact with patient.

2)      Diagnistic basis is call pattern and moephology of group of cells.

3)      Nuclear characteristics and cytoplasmic characteristic are both available for diagnosis.

4)      It is quick, convenient economic and painless procedure.

5)      Local anaesthesia is not requirsd.

6)      The process can be attempted at multiple site.

7)      It is a good diagnostic aid for radiotherapy and chemotherapy.

Limitation of FNAC

1)      False negative result is possible due to

a)       Fibrosis and selerosis in tumour.

b)      Highly vaseular tumour.

c)       Tumour necrosis.

2)      Aspirated material may not be adequate for proper diagnosis.

transmission of HIV infection

 

HIV ( Human immune deficiency virus ) is a lentivirus ( member of retrovirus family ) that causes AIDS in which progressive failure of immune system allow life threatening opportunistic infection and cancer to thrive. Infection with HIV occurs by the transfer of blood , semen , vaginal fluid , pre-ejaculate or breast milk. Within these body fluids HIV is present as both free virus particles and virus within infected immune cells the four major routes of transmission are:

                                                 ① Unsafe sex ② Contaminated Nidles ③ Breast milk ④ Transmission from an infected mother to her baby of birth.

                                        Normal social and domestic contact does not transmit the infection. Shaking hands, hugging, putting cheeks together or dry kissing are safe. There has been no confirmed case of transmission through saliva, through the virus may be present in the saliva of infected person. There is also no evidence of transmission by mosquitoes, bed-bugs or other blood sucking insects. Infection is not transmitted through air, food, water or fumiles.

characteristics of virus

 

Virus is obligate intracellular, non- filterable, ultra-microscopic parasite. Which require living animal, plant or bacterial cell for their reproduction. It has both characters, non- living ( outside the body / cell ) Living ( in the body )

           It has some unique features such as:-

       ① It has only one nucleic acid either DNA or RNA.

       ② It does'nt contain energy generating enzyme ATP.

       ③ Like inorganic matters, it can be cry stallised.

       ④ It passes through eclipse phase during invasion into host cell.

       ⑤ It is capable of bringing change in metabolic behavior of infected cell.

       ⑥ Some virus produce inclusion bodies ( group of viruses in cytoplasm ) in infected cell help in their diagnosis.

       ⑦ Infected cell produce interferon ( A type of chemical which protect from infection to another cell ) which protects non- infected cell from viral invasion.

       ⑧ For culture of virus living cell are necessary.

       ⑨ They produce cytopathic affect in the cell culture tissue.

      ⑩ Some virus may produce tumour are known as oncogenic viruses.

      ⑪ They don't multiply by binary fission.

      ⑫ They are small infecting agent (> soonm in diameter. )

      ⑬ They are antigenic and evoke production of antibody.

      ⑭ Immunity produced after infection is usually for the short time but some produce life long immunity such as small pox.

    ⑮ There are no staining materials used to visualise viruses.

    ⑯ Viruses don’t infect Fungi but infect bacteria.

    ⑰ Viruses are not sensitive to antibiotic.

    ⑱ Some viruses shows envelope which is ether sensitive.

    ⑲ Individual virus particle was previously known as elementary body.

    ⑳ Lipid of viral antigen is host antigen but protein of the envelope is viral antigen.