Post on 29-Aug-2019
transcript
Prof. Dr./ Wafaa Abd El-ghany
Professor of Poultry Dis.,
Fac. Vet. Med., Cairo Univ.
Definition Avian chlamydiosis is an acute fatal
or chronic infectious zonootic
respiratory disease of domestic, wild
and migratory birds.
The disease is characterized by nasal
and ocular discharge, diarrhea, loss
of weight, drop in egg production and
the mortality rate reached to 5-30%.
Presence of intracytoplasmic
elementary bodies (LCL) is
characteristic to the organism.
Psittacosis:
This term is given to the infection of
Psittacin or fancy (caged) birds like
parrots, parakeets, and also infection
of human.
Ornithosis:
This term is given to the infection of
non psittacin birds (Domestic birds).
Parrot Fever:
Referred to infection of parrots.
Economic Importance
1. Mortalities 5-30%.
2. Low feed conversion rate
and loss of body weight.
3. Drop in egg production.
4. Medication costs.
5. Zoonotic importance.
The causative agent
Chlamydophila psittaci (previouslyChlamydia Psittaci) (C.Psittaci).
It is a Gram negative, obligatoryintracellular organism.
This organism has different forms thatcould be detected in the impressionsmear stained by Giemsa, Gimenz,Castaneda, Macchiavello or stamp stainas:
1.Elementary body: Intracytoplasmic(LCL)bodies
2.Reticulate body: Intranuclear
Giemsa stain: intracellular chlamydial inclusion
(reddish-purple).
It is sensitive to tetracyclines,
chloraphenicol and erythromycin, resistant
to bacitracin, gentamycin and neomycin.
Disinfectant which affect lipids and cell
wall are effective (Quaternary ammonium
compound and lipid solvent).
It could be cultured in mice, embryonated
chicken eggs via Ys or CAM or on the tissue
culture.
There are 6 serotypes (A, B, C, D, E & F) as
typed by monoclonal antibodies or PCR.
Members of this serotype are differ in
virulence from low to high.
The causative agent
Susceptibility C.Psittaci infects all domestic and400 cages and wild birds (psittacinand non-psittacin).
Fancy and caged birds, turkeys,ducks, geese, pigeons, and ostrichesare highly susceptible.
Chickens are less susceptible.
C.Psittaci can infect human (due todirect contact with infected birds orinhalation of infected dropletscausing fatal pneumonia, heartthrombosis and even sterility).
All ages are susceptible but the
young are more susceptible.
The infection is usually in-apparent
or chronic latent asymptomatic.
Under stress factors, the latent
infection is changed into acute form
and the signs appear.
Concurrent infection with E.coli or
Salmonellae enhance the organism
pathogenicity.
Susceptibility
Mode of infection
C.Psittaci infection occur
horizontally either by inhalation
of infected dust or droplet or by
ingestion of contaminated feed and
water with infected droppings.
There is an evidence of low
percentage of vertical infection
through eggs (transoverian) in
ducks and sea gulls can occur.
Chronic carriers transmit the organism
without signs.
Biting of insects as ticks, lice and
mites.
Direct contact between the parents and
the young's in the nests (pigeons).
Wild birds are important in
transmission.
Incubation period:
5-60 days (age, virulence, health
conditions, management and dose)
Mode of transmission
Pathogenicity
Based on natural pathogenicity for
domestic fowl:
1. Highly virulent strains: acute
epidemics with 5-30% mortality.
2. Less virulent strains: slowly
progressive epidemics.
All strains have equal ability to
spread rapidly
Highly virulent strains Isolated from turkeys & occasionally
wild birds.
Most outbreaks serotypes: D
It is called “Toxigenic” → rapidly
fatal disease.
Causes extensive vascular congestion &
inflammation of internal organs.
Broad spectrum pathogenicity for Lab.
animal.
Serious infection (some fatal) in
humans.
Low Virulent Strains Slowly progressive epidemics.
Mortality less than 5% in
uncomplicated cases.
Isolated from pigeons & ducks and
occasionally from turkeys, sparrows
etc…. often accompanied by Salmonella
infection causes high mortality &
shedding.
Mostly serotype B & E.
Clinical signsTurkeys:
I Acute epidemic form (Highly virulent toxigenic strain)
Systemic fatal infection with:
Sudden death of 5-30% & morbidity rate 50-80%.
Nasal and ocular discharge, swollen eye lids, conjunctivitis and sinusitis.
Fever, off food and loss of weight (emaciation).
Yellow green gelatinous diarrhea.
Rapid drop in egg production (40-50%).
Turkeys:
II Infection with less virulent strain:
Inappetance.
Greenish diarrhea.
Slight drop in egg production.
Morbidity ranges from 5-20%.
Mortality ranges from 1-5%.
Complicated secondary infection with
bacteria, virus and protozoon induced
prolonged severe course and higher
mortalities.
Ducks and geese(water fowl):
In duckling, there are tremors,
trembling and staggered gait (in-
coordination).
Ocular and nasal discharge.
Greenish watery Diarrhea.
Emaciation, convulsion and death.
Morbidity rate 10-80%.
Mortality rate 1-30% (depending on
the age, health status and secondary
infection with Salmonella species).
Pigeons and pet birds:
Uncomplicated (acute disease):
Inappetance and emaciation.
Diarrhea.
swollen eye lids and conjunctivitis.
Rhinitis and sinusitis (dirty nostrils).
Respiratory distress and abnormal
respiratory signs (rattling signs).
Morbidity rate about 20%.
Complicated form:
Trichomoniasis, salmonallosis or paramyxo-
virus increase the severity of the disease.
Chickens:
They are relatively resistant.
Young birds acquired acute infection
and deaths.
The signs may be silent or temporary
(In-apparent infection).
Mortalities not exceeding 5%.
Nasal discharge, conjunctivitis and lacrimation
Parakeet: respiratory distress Chronic chlamydiosis (cachexia)
Post-mortem lesions Congestion of lungs and pneumonia.
All the body cavities are filed with
fibrinous exudates (Fibrinous pericarditis,
perihepatitis, and airsacculitis and
peritonitis).
Pancreas of pigeon enlarged and overlapped
the two duodenal loops with gray foci.
Catarrhal enteritis.
Liver and spleen are enlarged, dark and
covered with gray white foci.
Congestion of the visceral organs.
Fibrinous air sacculitisFibrinous perihepatitis
fibrinous pericarditis.
Pneumonia
Liver necrosis Enlarged and congested liver
congestion of spleen
Diagnosis Signs and lesions are suggestive.
Sections or impression smears of the
affected tissues or exudates or monolayer
of the infected cell culture could be
stained with Giemsa (purple), Giemenz
(red), Macciavello or Castanda and stamp
stains to detect intracellular cytoplasmic
or elementary bodies (LCL) (Levanthi, Cole
and Lelli). or reticulate (intranuclear)
bodies. Bodies etected under phase contrast
or dark field illumination microscope.
C.Psittaci can’t be propagated on
conventional cultural media but could be
isolated and propagated in:
Embryonated chicken eggs:
The eggs are inoculated via YS or CAM
and inocubated at 39 C for acceleration
of chlamydial growth for 6-7 days.
Death of the embryos with vascular
congestion after 3-10 days of
incubation. Sometimes 3 blind passage
in ECE is needed to obtain lesions in
embryos.
Touch impression smear for staining and
microscopic examination.
Diagnosis
Laboratory animal inoculation:
Intra peritoneal, intra cranial or intra
nasal inoculation of 3-4 weeks old mice (3-6
mice), death of mice after 5-7 days post
inoculation.
Intra peritoneal inoculation resulted in
peritonitis with splenomegaly.
Intra cranial inoculation resulted in
meningitis.
Intra nasal inoculation resulted in
pneumonia.
Diagnosis
Laboratory animal inoculation:
You can’t consider mice is negative except
after 3 blind passages.
Examination of the affected tissues by
cytochemical or immuno-flurescent method can
detect the organism in these tissues, also
impression smears of the affected tissues are
valuable.
Diagnosis
Tissue culture inoculation:
McCoy, Vero, Hela, mouse L cells, BHK21 and
BGM media are inoculated with the organism
then stained and examined microscopically.
Detection of bacterial antigen by PCR.
Serological tests like CFT, IF, IP, AGPT,
ELISA or latex agglutination test.
Diagnosis
Vascular congestion
Enlargement and congestion of the liver
and spleen, collected from chicken
embryos inoculated with C. psittaci. A
normal liver and spleen are shown in the
middle of the photo.
Enlarged and congested liver and
spleen collected from chicken embryos
inoculated with C. psittaci. A normal
liver and spleen are shown in the
middle.
Differential diagnosis
Colibacillosis.
Mycoplasmosis.
Fowl cholera.
Control1. Oxytetracyclin (15mg/kg bwt) in the
drinking water for a period for 5 days.
2. Chlorotetracyclin.
(treatment may be extended to 15-45 days)
in severe infection).
3. Usage of combined antibiotics to control
other associated infections as Salmonellae
and E.coli (quinolones like cipro, enro,
and danofloxacin) for 3-5 days in the
drinking water.
Prevention Sanitary measures must be adopted.
Different avian species and ages must
be reared away from each other.
Newly purchased (imported) birds,
especially pets must be quarantined
for 35 days (if positive discarded or
treated with tetracyclines till
recovery).
Prevent the introduction of birds from
the enzootic areas.
Avoid the contact with the free living
wild birds.
Thorough cleaning and disinfection
(iodophors or formaldhydes).
Prophylactic doses of antibiotics.
Regular testing of the birds using
serological tests.
Restrict the movement of people and
visitors.
Trials for vaccine preparation.
Prevention