Goodmorning

1st slide: Thank you for being here today. Im Cindy Dela Cruz from Fish Health Lab. I’m here to talk to you
about parasitology in fishes.

2nd slide: Our outline includes the diagnosis, staining, fixation and preservation, terms we usually
encounter in parasitology and the last one is the classification of parasites.

3rd slide: Before we begin, lets take a look in this fish model representing the different parasites with its
respective predilections sites. These include the ectoparasites or the external parasites found in the skin
and gills – the anchor worm, fish louse, skin flukes and etc. and the endoparasites or the internal
parasites found in the organs or muscle of the fish.

4th slide; before we go to the diagnosis of parasites in fishes, we 1 st tackle the guidelines and criteria for
parasitological examination.

• It is preferred that fish got examined on spot or submitted live to ensure retrieval of larger
portion of the parasites.

• Refrigeration is applicable only if your purpose in to retrieve macroscopic parasites such as the
fish louse, isopods etc. it should not be frozen. Bakit po? Kase may tendency na hindi na kakapit
of mafafall off yung parasites sa isda.

• So kung nagsampling kayo sa malayong lugar or di na kayang maidala ng buhay ang isda sa lab at
limited lang yung gamit nyo, walang microscope, it is best to fix tissues para maretrieve parin
yung parasites.

• Pag namatay na yung host, ang tendency is maghahanap na ng ibang host yung mga parasites
and they will fall off sa isda.

5th slide:

• So ito yung exception sa pagfreeze ng samples for para. Kung yung purpose mo is to
retrieve microsporidia, pwede mong ifreeze yung samples kase nareresist nila yung
freezing
• During examination sa mga malalaking isda diba usually mahirap sya irestrain, so ang
pinakamadaling way para irestrain yung isda is to put anesthetics/ms222 sa tubig nila which is a
no! no! pag yung analysis mo includes parasitology. Yung mga parasites na nakadikit sa skin, or
gills ay matatanggal.

• During examination, you should frequently drop saline or distilled water sa samples. Pag nagdry
na kase yung isda, mamamatay na yung mga microscopic parasites sa skin nila which lead to
false negative. Same lang din pag nagssmear ka ng skin or gills or kahit anong organ. It should be
wet. Pag yung samples mo ay marine fishes, you should use saline and freshwater fishes –
distilled water ang ginagamit.

• Pag nagsmear ka, like gills for example, naobserve mong uneven yung color yung gills, may part
na red, may part na pale. So yung kukunin mo para iview is yung part na may paleness. Or both
pwedeng kunin para maicompare mo normal at abnormal part ng gills.
6th slide: next part is the diagnosing of parasites

7th slide: during sampling, 30 samples po ang kukunin natin per pond. kung sa farm is may 2 ponds,
kukuha ka ng tig 30 per ponds kase yung parasites na present sa isa, pwedeng wala dun sa kabilang
pond.

8th slide: flashing- makati yung katawan ng isda pag madaming parasites. Flashing is yung way nila para
magkamot. Or yung iba nirurub yung katawan kaya nagcacause ng pagsusugat minsan sa skin.

Rapid opercular movement, pag may parasites sa gills lalo na pag overwhelming yung number,
nagkakaroon ng opercular movement dahil nagkakarron ng hypersecretion ng mucus sa gills as a normal
response ng katawan nila which cause irritation. Same is true with the skin. Nagsesecrete ng mucus pag
may parasites na present.

9th slide: Piping at the surface,- pag madaming parasites na ang present sa gills, nasisira na din ito which
causes depletion of oxygen. So ang tendency is maggugulp sila ng air para makahinga. So pag may
naobserve kang ganitong behavior, aside from poor water quality include nyo din po sa inyong
differential diagnosis ang pagkakaroon ng parasites sa mga isda.

Apperance of skin: during sampling, piliin po natin yung may mga abnormal apperance such as may
ulcers, nagdadark yung skin color, or yung mga may nodules o bukol sa katawan.

10th slide: the diagnostic techniques that we usually use in detecting parasites include gill biopsy, skin
cytology which will be discussed in the next slide. And the last is the necropsy which was previously
discussed by Doc Tinong.

11th slide: in the examination of gills or the gill biopsy, we 1 st lift the operculum take note of anything
unusual, such as pale pink streaks or areas of discoloration within the normally crimson red gill
tissue,White edges, frayed tips, holes, heavy mucus. Then remove the gill arch using forcep and scissors.
Make sure na manipis yung sample na mailagay sa slide para mapass thru yung light ng microscope sa
sample for better viewing. Then next step is drop saline solution or distilled water. Then put cover slip
and Observe for parasites. Usually they are motile kaya we should not let the sample dry.

12th slide: next is examination of parasites on skin. Using a scalpel blade we scrape the fish towards the
tail to obtain a sample of mucus. Then put the scrapings to a clean slide put a drop of saline and
examine under the microscope.

13th slide: so we move on now to the next topic, the preservation, fixation and staining of parasites.

14th slide: I prepared a table on how to fix, preserve and stain different parasites. For most protozoa, air
dry smear is used and stained in Giemsa. But for trichonids, silver nitrate is used. For myxosporeans,
freeze or fix the sample in 10% buffered formalin and are stained in Giemsa. For monogeneans, 1 st relax
them in hot water and transfer to alcohol-formalin-acetic acid then store in 70% alcohol. And as for
cestodes, nematodes, acanthocephalans, crustaceans parasites and leech, they are stored in 70%
alcohol.

15th slide: before we go to the different classification of parasites, we 1 st take a look on some of the
terminologies used in parasitology.

16th slide: read

18th slide: classification of parasites according to localization in the body. We have ectoparasites or yung
parasites na nakatira sa labas ng katawan ng isda. Endoparasites naman yung tawag sa parasites na
nakikita sa organs at muscle ng fishes and haemoparasites pag nakikita sa dugo.

19th slide: read; wihout the host, wala din parasites. Nakadepend lang sila sa host para mabuhay

20th slide: definitive host-

Intermediate host- dito sa intermediate host, magsstay lang sya for development ng larval stage
then lilipat na sa final or definitive host for sexual maturity

Reservoir host- in this, magsstay yung parasite til it matures but it does not harm the host but is
harmful sa ibang speceis.

Paratenic host: or what we call transport host.magsstay lang yung parasite don sa host as larval
stage at magaantay lang sya til it gains entry sa kanyang final host

21st slide: now we’ll go to the classification of parasites.

22nd slide: we have the protozoa, trematodes, cestodes, nematodes, acanthocephalans, and crustacean
parasites

23rd slide: READ

24th slide: READ

25th slide: Read

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27th slide: they have direct life cycle. READ

28th slide: READ

29th slide: READ

30th slide: ang pagkakaiba nila ni flagellates ay mas madaming hair structures yung ciliates and they are
shorter.

31st slide: the life cycle of the ciliates are completed in 3-5 days at 20 degrees. Pag malamig, mas
matagal yung life cycle nila.  activated, feeding stage in the life cycle of certain protozoa. Mature
trophonts leaves the host so magiging free-swimming sya then mageencyst,at saka magdidivide as many
as 2000 small tomites at kakawala sa cysts then pupunta ulit sa host nya.

32nd slide: ciliates causes mass mortality w/in short period. Diagnosis includes microscopic examination
of the skin and gills. You can see round or ovalparasites with cilia and horse shoe shaped macronucleus
typical of ciliates.

33rd slide: READ

35th slide: next classification is the trematodes

36th slide: READ

37th slide: READ

38th Slide: there are 2 types of monogeneans in terms of reproduction. The oviparous which is naglalay
sila ng eggs and viviparous which are live bearer. Example ng viviparous is yung ating gyrodactylus which
are generally found on the body and fins of fish. They have direct life cycle. Adults parasites carry a fully
developed embryo identical to the adult which in turn, carry young of the next generation. Yung
dactylogycrus, they are oviparous. Dactylogyrus attach to gills and lay eggs. When the eggs hatch, free-
swimming larvae emerge which are ciliated and are carried to a new host by water currents as well as by
their own movement. 

39th slide: you can see in the picture the koi infested with gill fluke. Nagkaroon sya ng paleness sa gills.

40th slide: READ

41st slide: Next trematode is the diginean parasites. READ

42nd Slide: digeneans have indirect life cycle. The adults lay eggs and become free swimming miracidium.
The free swimming larvae will invade the intermdiate host w/c is a mollusc and further develop into
cercaria. Yung narelease na cercaria, makakain ngayon ng maliliit na isda at magdedevelop into
metacercaria. And the final host, w/c are predatory fish or pwede din ibang animals, kakainin yung
infected fish at saka magigong adult diginea sa katawan ng final host.

43rd slide: READ

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45th Slide: next is cestodes

46th slide: READ

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49th Slide READ

50th Slide: Nematodes

51st slide: READ

52nd Slide: nematodes like the cestodes, have indirect life cycle.. they require 1 or more intermediate
hosts. 1st iintermediate hosts include non invertibrates which will be eaten by vertebrate hosts like the
small fishes. These infected small fishes are then eaten by predatory fish or larger animals where adult
nematodes are found.

53rd slide: READ

55th slide: Acanthocephalan

56th slide: these parasites have proboscis covered with many hooks thats why it is called thorny or spiny
headed worm.

57th slide: acanthocephalans also requires intermediate hosts for their life cycle. Halos same sila ng life
cycle ng nematodes and cestodes.

58th slide.

59th slide: READ

60th slide: Crustacean parasites

61st slide: crustacean parasites are called crustacean because they Resemble in their general
morphology with other crustaceans in having segmented body, covered with exoskeleton and jointed
appendages. We have 3 groups, barnchiura, copepoda and isopoda.

62nd slide: 1st we’ll have the branchiura which are the argulus spp. Or commonly called fish lice. READ

63rd: After mating the female deposits the eggs on a suitable substrate, such as aquatic plants. The eggs
hatch, producing metanauplius which infect fresh hosts and metamorphose to adults.

64th slide: READ

65th slideREAD

66th LSide: READ

67th slide: Copepods have direct life cycle, consisting of a freeliving planktonic nauplius stage, free
swimming infective copepodid stage, , pre-adult and adult stages. READ

68th slide: READ

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71st slide: Gravid females release eggs into a brood pouch within which the eggs embryonate, hatch and
undergo two moults, facilitating their rapid swimming performance. juvenile stages are then released
from the pouch, the parent then moults, feeds and subsequently produces the next batch of eggs.

72nd slide: READ