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Volume 27, Number 9—September 2021
Research

Risk Factors for Middle East Respiratory Syndrome Coronavirus Infection among Camel Populations, Southern Jordan, 2014–2018

Peter HollowayComments to Author , Matthew Gibson, Neeltje van Doremalen, Stephen Nash, Tanja Holloway, Michael Letko, Jacqueline M. Cardwell, Bilal Al Omari, Ahmad Al-Majali, Ehab Abu-Basha, Punam Mangtani, Vincent J. Munster, and Javier Guitian
Author affiliations: The Royal Veterinary College, Hatfield, UK (P. Holloway, J.M. Cardwell, J. Guitian); Glasgow University, Glasgow, Scotland, UK (M. Gibson); National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA (N. van Doremalen, M. Letko, V.J. Munster); London School of Hygiene and Tropical Medicine, London, UK (S. Nash, T. Holloway, P. Mangtani); Jordan University of Science and Technology, Irbid, Jordan (B. Al Omari, A. Al-Majali, E. Abu-Basha)

Main Article

Table 1

Descriptive statistics of Middle East respiratory syndrome coronavirus seropositivity in camel populations, Jordan, February 2014–December 2015 and October 2017–October 2018*

Variable
2014–2015 study

2017–2018 study
Total (data missing)
No. (%) seropositive
Total (data missing)
No. (%) seropositive
Region
Aqaba 301 269 (89) 233 143 (61)
Ma’an
123
108 (88)

132
95 (72)
Subregion
Aqaba East NR NR 145 93 (64)
Aqaba West NR NR 88 50 (57)
Ma’an East NR NR 67 55 (82)
Ma’an West
NR
NR

65
40 (62)
Season†
Winter 137 122 (88) 110 56 (63)
Spring 16 14 (88) 111 81 (75)
Summer 185 168 (93) NR NR
Fall
86
73 (84)

144
101 (70)
Age‡
0–6 m 9 (6) 4 (44) 39 26 (67)
>6 m–2 y 75 56 (75) 79 18 (23)
2 y–4 y 73 63 (86) 59 30 (51)
4 y–6 y 106 100 (94) 75 58 (77)
>6 y
170
158 (93)

152
132 (87)
Sex‡
M 94 79 (84) 84 40 (48)
F 330 298 (90) 281 198 (70)
Breeding male§
52 (6)
47 (90)

21 (12)
14 (67)
Herd size
1–10 153 123 (80) 162 97 (60)
11–20 79 68 (86) 75 48 (64)
>20
192
186 (97)

128
93 (73)
No. camel herds within a 15-min drive
<20 192 (25) 166 (86) 259 161 (62)
>20
207
192 (93)

106
77 (73)
Herd kept together as single group throughout the year
No 70 (17) 64 (91) 167 98 (59)
Yes
337
302 (90)

198
140 (71)
Herd has contact with other local herds
No 101 (114) 88 (87) 134 72 (54)
Yes
209
188 (90)

231
166 (72)
Herd has contact with distant herds
No 265 (20) 242 (91) 176 104 (59)
Yes
139
121 (87)

189
134 (71)
New camels are purchased¶
No 245 (17) 221 (90) 240 157 (65)
Yes
162
145 (90)

125
81 (65)
Quarantine >3 d after purchase before joining herd
No 97 (262) 92 (95) 101 67 (66)
Yes
65
53 (82)

24
14 (58)
Camels borrowed for breeding purposes#
No 164(17) 139 (85) 210 123 (59)
Yes
243
227 (93)

155
115 (74)
Herd-level borrowing of males
No 164(17) 139 (85) NR NR
Yes
243
227 (93)

NR
NR
Herd-level borrowing of females
No 322(17) 286 (89) NR NR
Yes
85
80 (94)

NR
NR
Camels loaned for breeding purposes
No NR NR 203 123 (61)
Yes
NR
NR

162
115 (71)
Camels in the herd used for racing
No 357 (17) 322 (90) 213 140 (66)
Yes
50
44 (88)

152
98 (64)
Camel is a racing camel‡
No NR NR 317 214 (68)
Yes
NR
NR

48
24 (50)
Water source**
Open ad lib 24 (17) 19 (79) 57 27 (47)
Household only 19 16 (84) 100 67 (67)
Trough only
364
331 (91)

208
144 (69)
Spring
No 384 (17) 348 (91) 312 214 (69)
Yes
23
18 (78)

53
24 (45)
Irrigation reservoir
No 398 (17) 360 (90) 335 223 (67)
Yes
9
6 (67)

30
15 (50)
Tanker
No 287 (17) 255 (89) 247 168 (68)
Yes
120
111 (93)

118
70 (59)
Tap
No 111 (17) 101 (91) 198 124 (63)
Yes
296
265 (90)

167
114 (68)
Well
No 356 (17) 321 (90) 276 189 (69)
Yes
51
45 (88)

89
49 (55)
Water source not shared with herd, household use only
No 388 350 (90) 265 171 (65)
Yes
19
16 (84)

100
67 (67)
Camel has nasal discharge at time of sampling‡
No NR NR 303 (54) 204 (67)
Yes
NR
NR

8
8 (100)
Closed herd††
No NR NR 328 227 (69)
Yes NR NR
37 11 (30)

*Variables reference the 1-year period before sampling, with the exception of herd size, camel is a racing camel, and a priori variables: age, sex, and region. Because of the potential influence of maternal immunity, camels <6 m of age have been excluded from all variables except age. NR, not recorded. †Weighting adjusted. ‡Individual camel–level variables (all other variables being herd-level). §Nonracing adult males (>2 y), likely in the herd for breeding purposes. ¶Camels purchased are locally bred; Jordanian Ministry of Agriculture Camel Import Regulations and Conditions allow import only for live camels for direct slaughter. #In the 2014–2015 study, results for camels are borrowed for breeding purposes (male, female, or both) and camels are borrowed for breeding purposes (male) were the same (i.e., all herds that borrowed camels for breeding purposes borrowed males, and some of these herds also borrowed females. In the 2017–2018 study, the sex of camels borrowed or lent for breeding purposes was not recorded. **Open ad lib indicates irrigation reservoir or spring water sources were used; household only indicates water source was not shared between household and herd; trough only indicates only tanker, tap, or well sources were used. ††Closed herd indicates herd owners answered no to all of the following variables: borrowing, lending, purchasing, racing, and contact with local or distant herds (2017–2018 study only, missing data 2014–2015).

Main Article

Page created: June 22, 2021
Page updated: August 17, 2021
Page reviewed: August 17, 2021
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