SEVERE PARASITISM – A HINDRANCE TO EFFECTIVE NEWCASTLE DISEASE CONTROL IN VILLAGE CHICKENS?L.C. Bebora1, N. Maingi1, P.N. Nyaga1, P.G. Mbuthia1, L.W. Njagi1, M. Githinji2, D.C. Kemboi1 and H.W. Chege1

1 University of Nairobi, P.O. Box 29053 – 00625, Nairobi, Kenya2 Ministry of Livestock, Central Vet. Laboratories, Private Bag -00625, Kabete, Kenya

PRESENTED AT THE 3RD RUFORUM BIENNIAL CONFERENCE ON 24TH TO 28TH SEPTEMBER 2012 IN ENTEBBE, UGANDA

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Format of presentation

1.Indigenous chickens2.Newcastle disease3.Chicken parasites4.Objective; Hypothesis5. Study design6. Results7. Conclusion

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Indigenous cocks

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Indigenous hens

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Naked-necked cock and hen

University of Nairobi

Indigenous chickens

•They are of different colors, sizes and design•They are of dual purpose – meat and eggs•They are preferred due to their taste•The yellow color of their egg yolk is appetizing•They are also believed to be organic

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Indigenous chickens (cont.)

•Thus, their eggs sell more expensively than those of commercial breeds

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Indigenous chickens (c0nt.)

•Normally, indigenous chickens are kept by resource-poor persons•They contribute immensely towards the socio-economic aspect of these people•They serve as:-Source of proteinSource of income (as bank for quick money when needed)Ceremonial items (slaughtered for special guests; gifts; for religious ceremonies, etc) 8

Indigenous chickens (cont.)

•An average household keeps a flock of between 10 to 30 birds•Thus, in total, these birds constitute over 70% of the estimated 36 million birds in Kenya (kept by almost every village household)•This type of chicken industry is taken as one of the biggest untapped economic potential in the country

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Indigenous chickens (cont.)

•Because the owners could make money if they kept larger flocks•When the people’s income is increased the cumulative income for the country increases•One of the reasons why they don’t maintain large flocks is death due to Newcastle disease

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Newcastle disease

•ND causes high mortality, up to 100%•Being a viral disease, ND can be effectively controlled only by vaccination•Effectiveness of the ND vaccination is reduced when birds are immune-suppressed

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Newcastle disease (cont)

ND is diagnosed mainly by:-high mortality exhibited by the affected birds-greenish diarrhoea-on post-mortem examination, hemorrhages in various organs, especially the proventriculus and trachea

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Hemorrhagic lesions in pro-ventriculus

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Another manifestation of Newcastle disease

Hemorrhages in the trachea

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Newcastle disease (cont)

•The overall aim of this study was to see if deaths of these birds can be reduced by introducing ND vaccination•This will: - increase the number of chickens per household -improve productivity of the birds, in terms of numbers, egg and meat production

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Newcastle disease (cont)

-empower the people economically

-contribute towards poverty alleviation

From a previous study, these birds were shown to carry heavy

loads of parasites

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Chicken parasites

•Some of parasitic diseases, like coccidiosis, can cause high mortalities•Most other parasites lead to emaciation, reduced production and stress, through:Blood suckingCausing irritation to the birds Nutrient consumption

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Chicken parasites (cont) •Stress is associated with immune-suppression•Therefore, parasitism is expected to cause immune-suppression in the chickens•Effective control of parasites is, therefore, expected to improve effectiveness of ND vaccination •Through production of high immunity/titers in the chickens• which will protect the chickens in the event of disease challenge

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Chicken parasites (cont)

•Different types of parasites that affect chickens from Mbeere District will be given in the Results section

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Previous observations on Mbeere chickens

•Njagi et al (2008 )established that ND is endemic in Mbeere District (thus need for vaccination)•Sabuni (2009) demonstrated that these chickens from Mbeere are heavily infected with ecto – and hemo-parasites

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Underlying questions to this

•Will the severe state of parasitism lower the chickens’ immune response (through continued stress), so as to be a hindrance to effective ND control in the chickens?•If so, to what level does it lower the immune response?A positive answer to this will emphasize the need for parasite control as we encourage the farmers to vaccinate their chickens

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ND vaccination and parasitism

Hypothesis: . The parasite burden causes significant suppression of immunity so as to lower ND vaccination response in the village chickens. Current presentation: Is on baseline data collection – to establish the current findings on chickens from Mbeere, with respect to parasite carriage and endemicity of ND in the area

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Aim of this particular study

•To establish the current status of parasite carriage and endemicity of ND (indicated by presence of antibodies) in Mbeere chickens•In addition to the ecto- and hemo- parasites, this study covered intestinal parasites•So as to decide whether or not there is still need to advocate for ND vaccination

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Information on the study area

•Mbeere District, Eastern Province, Kenya•It lies between latitude 0020’ and 0050’ South and longitude 37016’ and 37056’ East•Altitude 500 to 1200 metres above sea level•Long rains: March to June•Short rains: October to December•Daily temperature ranges between 20 and 30 oC

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Study design

•Study was cross-sectional, done during wet season.• Twenty four (24) chickens of various ages (chicks, growers, adults) were used. •For parasitological study, post-mortem examination of the birds was done according to Charlton et al. (2006),

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Study design (cont)

•Harvesting and identification of endo- and ecto-parasites were done according to MAFF (1986) and Sabuni et al. (2009). •For the serological study, hemagglutination inhibition test was used to determine the respective antibody titres (OIE, 2000).

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Study design (cont)

The laboratory procedures were carried out at the Department of Veterinary Pathology, Microbiology and Parasitology; College of Agriculture and Veterinary Sciences (CAVS), Kabete; University of Nairobi.

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Results: Parasites

•All the 24 chickens had lice infestation; some of the counts being as high as 222 per bird•17 (70.8%) of the chickens had mites on their body surface or their legs; the most prevalent was Dermanyssus gallinae (82.3%)•15 chickens (62.5%) had the stick-tight flea, Echinophaga gallinacean•6 chickens (25%) had the soft tick, Argus persicus

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Leg mites

Fleas

Soft ticks

Results: Parasites (cont)

Results: Parasites (cont.)

•This showed that the chickens were multiply infested with ectoparasites

•All the birds also showed multiple infections with gastrointestinal parasites• Nematodes (96%), cestodes (87.5%) and coccidia (25%)

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Tetrameres Ascarids

Tape worms

Results: Parasites (cont)

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Coccidial hemorrhages - cecum Coccidial oocysts

Results: Parasites (cont)

Results: Parasites (cont)

•19 chickens (79.2%) had hemoparasites,including Plasmodium, Leucocytozoon and Aegyptinella species•Plasmodium was the most prevalent (79%; 19/24)

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Plasmodium parasites

Results: Parasites (cont)

•The results thus showed that the chickens from Mbeere still carried heavy loads of various types of parasites•The ecto- and hemo-parasites were similar to those found by Sabuni in 2009

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Serological results

•Serum samples from the 24 chickens studied were found to be positive for presence of ND antibodies, with 100% specificity•Titres ranged from 16 to 256, with a geometric mean titre of 65.85•All the age groups had ND antibodies; those of chicks were considered to be maternal

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Titer

Age Samples

1:2 1:4 1:8 1:16 1:32 1:64 1:128 1:256 GMT

Chicks

7 - - - 1 - 4 1 1 70.66

Growers

8 - - - 1 2 4 - 1 53.82

Adults

9 - - - - 1 5 3 - 74.65

TOTAL

24 0 0 0 2 3 13 4 2 65.85

HI titres for the 24 birds studied

Chicks <2 months, Growers – 2-8 months, Adults >8 months, GMT – Geometric mean

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Serological results (cont)

Results indicated that ND was still endemic in Mbeere and the village chickens; confirming the findings of Njagi (2008)

Conclusion

•The study demonstrated continued endemicity of ND in chickens of Mbeere District•This observation emphasises the need to vaccinate the birds, so as to maintain high titres for protection against the disease

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Conclusion (cont)•The study also demonstrated high carriage of various types of parasites by these chickens•This intense parasitism may be responsible for continuous stress and immune-suppression to the chickens•Total parasite control would, therefore, be one of the necessary measures to be taken in order to implement effective vaccination against ND

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Continuing study

•Another study is currently going-on to determine the extent at which parasite burden depresses the immune response to ND•This will provide more information and help in formulation of parasite treatment and vaccination regimes

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Acknowledgement

•RUFORUM for providing funds for the study•Government of Kenya and University of Nairobi for providing physical space and technical help•Farmers and extension officers in the area for their participation•The present audience for listening to me

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THANK YOU

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