A longitudinal study of the incidence of major endemic and epidemic diseases affecting semi-scavenging chickens reared under the Participatory Livestock Development Project areas in Bangladesh

Figures & data

Figure 1. Proportional mortality rates of common endemic and epidemic disease affecting chickens reared in the PLDP area of Bangladesh.

Table 1.  An overview on the study population and diseases observed

Period of observation	Number of birds recorded on visit day	Total number of deaths	Distribution of diseases							Total undiagnosed	Mixed infections
			ND	FP	FC	Sal	Coli	Asp	IBD
January 2002	1490	14	2	0	0	0	0	0	5	5	2
February 2002	1497	68	10	4	3	3	8	1	2	33	4
March 2002	868	95	7	7	8	3	6	1	2	59	2
April 2002	4782	33	3	3	1	1	1	2	3	17	2
May 2002	4480	65	17	7	0	3	3	0	0	27	8
June 2002	3010	67	12	9	8	1	8	0	2	19	8
July 2002	4872	93	22	4	11	11	4	0	3	29	9
August 2002	846	84	20	1	7	8	14	0	0	16	18
September 2002	684	61	9	1	1	5	1	0	1	42	1
October 2002	1333	51	17	0	4	7	4	0	0	15	4
November 2002	3043	26	7	1	0	0	0	0	3	12	3
December 2002	11418	75	18	6	6	5	3	0	0	27	10
January 2003	5951	122	14	15	0	14	14	0	0	49	16
February 2003	13600	132	15	0	6	12	6	0	4	72	17
March 2003	1595	112	7	6	17	6	1	0	0	51	24
April 2003	1684	101	10	43	7	4	12	0	0	24	1
May 2003	522	28	4	3	4	4	0	0	0	13	0
Total (17 months)	61 675	1227	194	110	83	87	85	4	25	510	129
ND, Newcastle disease; FP, fowlpox; FC, fowl cholera; Sal, salmonellosis; Coli, colibacillosis; Asp, aspergillosis; IBD, infectious bursal disease.

Table 2.  Temporal distribution of cases of mixed infection

Month	Mixed infection categories
	ND + FC	ND + FP	ND + IBD	ND + Sal	ND + Coli	Sal + IBD	Coli + IBD	FC + Asp	FC + FP	FC + Sal	FC + Coli	Sal + Coli	FC + Coli + ND	Total
January 2002	–	–	–	–	1	–	1	–	–	–	–	–	–	2
February 2002	–	–	1	1	1	–	–	–	–	–	1	–	–	4
March 2002	–	1	–	1	–	–	–	–	–	–	–	–	–	2
April 2002	–	1	–	–	–	–	–	1	–	–	–	–	–	2
May 2002	–	–	–	6	–	––	–	–	1	1	–	–	–	8
June 2002	–	1	–	3	2	1	–	–	–	1	–	–	–	8
July 2002	3	–	–	–	–	–	–	–	–	4	2	–	–	9
August 2002	1	–	–	1	4	–	–	–	–	7	5	–	–	18
September 2002		–	–	1	–	–	–	–	–	–	–	–	–	1
October 2002		–	–	–	–	–	–	–	–	2	2	–	–	4
November 2002	1	–	–	1	–	–	–	–	–	1	–	–	–	3
December 2002	2	–	–	4	4	–	–	–	–	–	–	–	–	10
January 2003	1	–	–	2	3	–	–	–	–	2	6	1	1	16
February 2003	3	–	–	3	1	–	–	–	–	5	5	–	–	17
March 2003	4	–	–	1	1	–	–	–	–	12	6	–	–	24
April 2003	1	–	–	–	–	–	–	–	–	–	–	–	–	1
May 2003	–	–	–	–	–	–	–	–	–	–	–	–	–	0
Total	16	3	1	24	17	1	1	1	1	35	27	1	1	129
Proportional distribution (%)	12.40	2.33	0.78	18.60	13.18	0.78	0.78	0.78	0.78	27.13	20.93	0.78	0.78	100
ND, Newcastle disease; FP, fowlpox; FC, fowl cholera; Sal, salmonellosis; Coli, colibacillosis; Asp, aspergillosis; IBD, infectious bursal disease.

Figure 2. Proportional mortality dynamics of semi-scavenging chickens in Bangladesh caused by endemic and epidemic diseases.

Table 3.  Occurrence of major diseases in birds aged below and above 60 days

Age	n	Diseases: total positive cases (%)								Undiagnosed deaths
		ND	FP	FC	Salmonellosis	Colibacillosis	IBD	Aspergillosis	Mixed
≤60 days	315	30 (9.52)	71 (22.54)	13 (4.13)	18 (5.71)	14 (4.44)	13 (4.13)	4 (1.27)	36 (11.43)	116 (36.83)
>60 days	856	161 (18.81)	34 (3.97)	65 (7.59)	65 (7.59)	65 (7.59)	11 (1.29)	–	84 (9.81)	371 (43.34)
Difference in occurrence	1171	P=0.00	P=0.00	P=0.04	P=0.27	P=0.06	P=0.00	–	P=0.42	–
Fifty-six samples missed to have age information.

Table 4.  Occurrence of diseases in the four breeds investigated

Breed	Diseases: total positive cases (%)								Undiagnosed
	ND	FP	FC	Salmonellosis	Colibacillosis	Aspergillosis	IBD	Mixed
Sonali (n=112) (♂Rhode Island Red + ♀Fayoumi)	31 (27.68)	4 (3.57)	6 (5.36)	6 (5.36)	3 (2.68)	1 (0.89)	2 (1.79)	21 (18.75)	38 (33.93)
Deshi (n=933) (non-descriptive)	140 (15.01)	80 (8.57)	63 (6.75)	70 (7.50)	64 (6.86)	0 (0)	7 (0.75)	84 (9.00)	425 (45.55)
Rhode Island Red (n=20)	2 (10.00)	4 (20.00)	2 (10.00)	0 (0)	2 (10.00)	0 (0)	1 (5.00)	1 (5.00)	8 (40.00)
Fayoumi (n=158)	21 (13.29)	22 (13.92)	11 (6.96)	11 (6.96)	16 (10.13)	3 (1.90)	15 (9.49)	21 (13.29)	38 (24.05)
Overall difference	P=0.00	P=0.01	P=0.81	–	P=0.08	–	P=0.00	P=0.01	–
Comparative occurrence
Sonali versus Deshi	P=0.00	P=0.07	–	–	–	–	P=0.26	P=0.00
Sonali versus Rhode Island Red	P=0.09	P=0.01	–	–	–	–	P=0.37	P=0.13
Sonali versus Fayoumi	P=0.00	P=0.00	–	–	–	–	P=0.01	P=0.22
Deshi versus Rhode Island Red	P=0.53	P=0.08	–	–	–	–	P=0.04	P=0.53
Deshi versus Fayoumi	P=0.57	P=0.03	–	–	–	–	P=0.00	P=0.09
Fayoumi versus Rhode Island Red	P=0.68	P=0.47	–	–	–	–	P=0.51	P=0.13

Table 5.  Occurrence of diseases in male and female birds

Sex type	Diseases: total positive cases (%)								Undiagnosed
	ND	FP	FC	Salmonellosis	Colibacillosis	Aspergillosis	IBD	Mixed
Male (n=235)	37 (15.74)	10 (4.26)	16 (6.81)	26 (12.06)	15 (6.38)	0 (0.0)	3 (1.28)	4 (1.70)	124 (52.77)
Female (n= 987)	157 (15.91)	100 (10.13)	66 (6.69)	61 (6.18)	70 (7.09))	4 (0.41)	21 (2.13)	123 (12.46)	385 (39.01)
Differences (P)	0.95	0.01	0.95	0.01	0.70	0.33	0.40	0.00	–

Table 6.  Occurrence of ND in vaccinated and unvaccinated birds

Immune status	ND occurrence (%)		Total birds observed	Odds ratio (95% confidence interval)	χ^2 value	P value
	Positive	Negative
Vaccinated	101 (single) + 31 (mixed) = 132 (29.66)	313	445	2.24 (1.66–3.02)	32.74	0.00
Unvaccinated	93 (single) + 31 (mixed) = 124 (18.84)	658	782
	Total = 256	971	1227