a) Describe the adaptations of Schistosoma spp to their parasitic mode of life. b) Outline five measures that can be employed to prevent and control the spread of the parasite.

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 a)  Describe  the  adaptations  of  Schistosoma  spp  to  their  parasitic  mode  of  life.
The  parasite  utilizes  two  hosts;  the  snail  and  humans;  to  increase  chances  of  transfer  of  the parasite  from  one  place  to  another;  have  suckers  for  attachment  to  host  walls;  to  prevent  them from  being  dislodged;  the  parasite  produces  many  larval  forms  (e.g.  miracidia,  cercariae  and redia)  in  snails;  to  increase  chances  of  transmission  and  survival;  as  this  feature  poses barriers/difficulties  in  efforts  aimed  at  eradicating  the  parasite;  cercariae  larvae  and  eggs  of the  parasite  have  glands  that  secrete  lytic  enzymes;  which  soften  the  tissues  of  humans/snails; to  allow  for  penetration;  chemical  substances  produced  by  the  adult  worm;  protects  the parasite  from  the  action  of  the  hosts’  defense  mechanisms;  they  exist  as  separate  sexes;  with the  male  carrying  the  female;  this  ensures  that  eggs  produced  by  the  female  are  fertilized before  being  shed  into  the  blood  stream;  Max.  15  mks

 b)  Outline  five  measures  that  can  be  employed  to  prevent  and  control  the  spread  of  the parasite
 Proper  disposal  of  human  waste;  urine  and  faecal  material  should  not  be  disposed  in  water bodies  to  avoid  contamination  by  the  eggs  or  adult  worms;  drainage  of  stagnant  water  pools and  use  of  molluscides  to  kill  the  intermediate  hosts  (snails);  avoid  swimming/bathing  in snail-infested  water  bodies;  wearing  protective  clothing  such  as  gloves  and  gumboots  when working  or  walking  in  swampy  areas;  personal  hygiene  that  includes  washing  hands  after visiting  the  toilet  and  drinking  of  boiled  or  chemically  treated  water  to  kill  the  eggs  and  the larval  forms  in  the  water;  proper  treatment  of  infected  persons;
  Max.  5  mks 

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