ENTEROBIUS VERMICULARIS ( Thread worm or pin worm )

There are two types of adult of Enterobius vermicularis of which one is male and the other is female .

Adult Male Worm –

1. Shape – It is small and white in colour . It is spindle shaped .

2. Size -  It measures about 2 to 4 mm in length and 0.1 to 0.2 in breadth ..

3. The oral end – A pair of cervical alae is present at the anterior extremity . There is

                                      no buccal cavity . The posterior end of the oesophagus is dilated .

4. The posterior end – The posterior third of the body is coiled ventrally and sharply    

                                  truncated .

5. Anus -  Anus is present at the posterior end .

6. Genitalia -         

                      (a)  Testis                                            –  It has a single tubular testis .

         (b) Seminal vesicles                           –  Two in number .

                      (c)  Ejaculatory duct is present .

               (d) Terminal copulatory spicule          – It is about 70μin length without

                                                                               gubernaculums .

(e)    Caudal alae is present at the posterior end .

(f)    Three pairs of postanal sessile papillae and a pair of sessile papillae are present .

Adult Female Worm

1. Shape – It is small and white in colour . It is spindle shaped .

2. Size – It measures about 8 to 12 mm in length and 0.3 to 0.5 mm in breadth .

3. The oral end – A pair of cervical alae is present at the anterior extremity . There is

                                     no buccal cavity . The posterior end of the oesophagus is dilated .

4. The posterior end – The posterior extremity is straight and tapering .

5. Anus – The anus is at the junction of the middle and posterior third of the body .

Genitalia –

i)                    Oviduct are present

ii)                  Uterus is present

iii)                Vagina is present .