Livestock Research for Rural Development 29 (4) 2017 Guide for preparation of papers LRRD Newsletter

Citation of this paper

The prevalence and causes of mastitis in lactating traditionally managed one-humped camels (Camelus dromedarius) in West Pokot County, Kenya

K C Toroitich, G K Gitau1, P M Kitala and G C Gitao2

Department of Public Health, Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Nairobi
gkgitau@uonbi.ac.ke
1 Department of Clinical Studies, Faculty of Veterinary Medicine, University of Nairobi
2 Department of Veterinary Pathology, Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Nairobi

Abstract

A cross sectional study was conducted to determine the prevalence and causes of mastitis in 95 clinically healthy lactating and traditionally managed one-hump camels (Camelus dromedarius) in Kongelai, Kacheliba, Konyao, Kasei, Kiwawa and Alale divisions of West Pokot County, Kenya. Fifty two households were conveniently selected from a list provided by Kenya Camel Association West Pokot County based on the presence of a lactating camel in the household.

A total of 380 quarter milk samples (56 from Kongelai division, 40 from Kacheliba division, 8 from Konyao division, 148 from Kiwawa division, 92 from Kasei division and 36 from Alale division) were collected observing asepsis. The samples were transferred to the laboratory for bacterial culture. Of the 380 quarter milk samples cultured, 169 samples tested positive for subclinical mastitis which gave a prevalence of quarter infection at 44.5% (169/380). At animal (camel) level the prevalence of subclinical mastitis was 76.8% (73/95 camels).Therefore the results of this study have shown that subclinical mastitis is prevalent in dromedary camels of West Pokot County. The same results showed that, the right hind quarter (RHQ) was the most frequently infected quarter (prevalence of 12.1% (46/380)) followed by the right fore quarter (RFQ) (prevalence of 11.3% (43/380)). The two left quarters, left fore quarter (LFQ) &left hind quarter (LHQ) were least infected. This could point out that the Pokot herders tended to milk the right quarters more often and leave the left quarters to be suckled by the calves and because of poor & unhygienic milking procedures the right quarters become more infected.

The most predominant isolated bacterium was gram-positive Staphylococcus aureus with prevalence of 36.0% (49/136) followed by gram-negative Escherichia coli with prevalence of 27.2% (37/136). Streptococcus agalactiae & Staphylococcus epidermidis were the third predominant isolates with prevalence of 9.6% (13/136) each. Micrococcus spp & pseudomonas were the least isolates with less than 1% prevalences. A diagnosis of ‘no bacterial growth’ was made in 22 cases which is 16.2% (22/136). Several mastitis control strategies should be put in place such as milking procedures, milking order, strict hygiene, post milking teat disinfection, use of antibiotic dry-off therapy and the culling of persistently infected camels.

Keywords: dromedary camels, subclinical mastitis, quarter samples, West Pokot, Kenya


Introduction

In spite of it living in harsh environments of semiarid and arid zones, the dromedary camel is able to produce milk in valuable quantity (Schwartz and Dioli, 1992; Faye, 2005). However, like other dairy animals, dromedary camels could be affected by udder infections such as mastitis, a complex disease occurring worldwide among dairy animals, with heavy economic losses largely due to clinical and subclinical mastitis. The later requires indirect means of diagnosis (Matofari et al., 2003). Camel mastitis is both medically and economically important due to its multiple hazardous effects on human health and animal production (Younan, 2004; Akweya et al., 2010; Njage et al., 2010). In addition to these health concerns, mastitis reduces production (Musinga etal., 2008) and quality (Matofari et al., 2003; Mengistu et al., 2010) of milk of traditionally managed camels. In the arid and the semi-arid areas of Kenya (ASALs), milk is consumed fresh or sour posing a health hazard to consumers (Younan, 2004). It has recently come to light (Younan et al., 2001) that infections of the udder of lactating camels are quite widespread. Generally, bacteria in milk can occur through colonization of the teat canal or an infected udder (clinical or subclinical mastitis), or as contaminants (Younan, 2004).

Evidence indicates that subclinical mastitis causes suffering of dairy animals, reduce milk yield, alters milk properties, impairs preservation and processing and is of a public health concern for consumers of camel milk (Fthenakis and Jones, 1990; Tibary and Anouassi, 2000). Very little is known about mastitis concerning their aetiology and occurrence in Camelidae (Abdel Gadir et al., 2006; Kalla et al ., 2008). However, cases of mastitis in camel have recently been reported in Saudi Arabia (Barbour et al., 1985); Egypt (Mostafa et al., 1987); Somalia (Abdurahman et al., 1991); Ethiopia (Bekele and Molla, 2001); Israel (Guliye et al., 2002) and Kenya (Matofari et al., 2003).


Materials and Methods

Description of the Study area

The study was carried out in West Pokot County in the former Rift Valley Province of Kenya as shown in Figure 1.

Figure 1. Map of Kenya showing West Pokot County the study area

The County borders Uganda to the West, Trans Nzoia and Elgeyo-Marakwet Counties to the South, Turkana County to the North and East and Baringo County to the South East. Geographically, it lies between Latitudes 1 010’ and 30 40’ N and Longitudes 340 50’and 350 50’E (Macmillan Education Ltd., 1999). It has a total area estimated at 9,100 square kilometers and stretches a distance of 132 km from North to South. The County is made up of four sub-counties and14 divisions. The study which took place between the months of August and November 2012 was only carried out in six divisions as shown below in Figure 2.

Figure 2. Map of West Pokot County showing the six study divisions

These divisions are the only divisions with the highest population of camels in West Pokot County and they are located along the border between Kenya and Uganda.

Study Design

The study was a cross-sectional study undertaken on 95 lactating and traditionally managed one-hump camels (Camelus dromedarius) in 52 randomly selected households (manyattas) in West Pokot County. These households (manyattas) were the sampling units.

Data collection

Data on household demographics (human and animal) and known and/or reported diseases of camels, and animal level factors (each camel) such as age, parity number, stage of lactation, breed, current milk yield, milk abnormalities, whether the camel has had mastitis before and presence of udder/teat lesions were collected and recorded in a semi-structured questionnaire (SSQ) during sampling. Data were also gathered through interviews administered to the household head or any other household member conversant with the camel management.

Sample size determination for the number of milk samples

The following formula was used to calculate the sample size (Dohoo et al., 2003):

n = Zα2pq/L2, where, n=sample size, = the value of z that gives 95% confidence interval (1.96), p = a priori prevalence (estimated prevalence), q = 1-p and L = allowable error.

The prevalence of mastitis in camels in Kenya was estimated at 25% as was reported by Younan et al., (2001). Thus adopting a p of 25% and L of 5%, then;

n = (1.962*0.25*0.75)/ (0.05)2 = 290 (quarter milk samples).

Collection of milk samples

Prior to the commencement of sample taking, the camel owner’s consent was obtained after explaining the purpose and objective of the study. Milk samples were then aseptically collected from each individual quarter from 95 lactating camels (14 from Kongelai, 10 from Kacheliba, 2 from Konyao, 37 from Kiwawa, 23 from Kasei and 9 from Alale division) during either morning, midday or evening milking time depending on what was logistically convenient. This was done after the calf was allowed to suckle to allow milk let down. Visual examination (by observation and palpation) of all the quarters was also carried out.

About 20 ml of milk was collected from each quarter directly into clean and sterile sample bottles that were clearly labeled and immediately stored in cool boxes with ice packs before refrigeration in the evening at around 5 0C and later transported in cool boxes with ice packs to the Bacteriology Labora­tory at the Department of Pathology, Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Nairobi for bacterial culture.

Bacteriological Examination and Isolations

After culturing, bacteriological examination was carried out following standard methodslaboratory and field handbook on bovine mastitis – (1987), Sears et al – (1993) and Quinn et al – (1994) to identify major bacterial agents associated with mastitis.

Statistical Data Analysis

All data collected were entered in Microsoft Excel 2007 worksheet as database and exported to Instat Plus for statistical analysis. Descriptive statistics were generated using the same statistical package. Differences in proportions were assessed using the chi square at 5% level of significance in univariate analysis.


Results

Characterization of camel milking practices

The results of the study showed that, many Pokot camel owners generally milked their camels thrice a day (90.4% (47/52)); at dawn or early in the morning; at 10 am (limo in Pokot) and at night about 8.00pm (2-3 hours after returning from grazing). Only 9.6% (5/52) milked their camels twice a day. Majority of the milkers (82.7% (43/52)) washed their hands once before milking all livestock beginning with goats, cows and lastly the camels compared with 17.3% (9/52) who do not wash their hands at all. On washing the udder before milking, 76.9% (40/52) do not wash the udder. They believed that the calf would clean the udder by suckling. About 7.7% (4/52) washed the udder before milking. These were mostly camel keepers around trading centres. None respondents were 15.4% (8/52).

Most (75% (39/52)) of the treatment of camel mastitis was done by the owners. Few (26.9% (14/52)) went for some assistance from the Community based animal health workers (CBAHWs). Veterinarians (VOs) and animal health assistance (AHAs) were not consulted on treatment of mastitis. During mastitis infection, 75% (39/52) do not follow the milking order where you start milking the clean camels first and the infected camels last.

Amongst the Pokot people, camels are mostly milked by young boys (herders) (42.3% (22/52)) and adult women (30.8% (16/52)). In the absence of women, the men (26.9% (14/52)) could also milk the camels as shown in Table 1.

Table 1. Camel milking practices

Household practices

Frequency

Percentage (%)

Milking Rates

Thrice a day

47

90.4

Twice a day & below

5

9.6

 

Wash hands
before milking

Yes

43

82.7

No

9

17.3

 

Wash the udder
before milking

Yes

4

7.7

No

40

76.9

No respond

8

15.4

 

Who milks
the camels

Owners

14

26.9

Wives

16

30.8

Herders (young boys)

22

42.3

 

Who treats camels
with mastitis

V.O

0

0

AHA

0

0

Self

39

75

CBAHWs

14

26.9

 

Follow milking order
during mastitis

Yes

13

25

No

39

75

Household demographics
Age and sex distribution

Of the 52 households interviewed 86.5% (45/52 households) were headed by males and 13.5% (7/52 households) were headed by females. 100% (52/52) of the households were settled in communal land; therefore most of the camels were reared in communal range land. The age brackets of the camel owners were <20 yrs 3.8% (2/52); 21-30 yrs 15.4% (8/52); 31-40 yrs 36.5% (19/52); 41-50 yrs 26.9% (14/52); 51-60 yrs 9.6% (5/52) and >60 yrs 7.7% (4/52) as in Figure 3 below. Majority of the camel owners were between 31 and 40 years of age while the least were below 20 yrs and above 60 years of age.

Figure 3. Age and sex distribution of the households' heads interviewed
Laboratory results on bacterial culture and identification

A total of 380 quarter milk samples (56 from Kongelai division, 40 from Kacheliba division, 8 from Konyao division, 148 from Kiwawa division, 92 from Kasei and 36 from Alale) from 95 apparently clinically healthy dromedary camels were collected and cultured in the laboratory to identify subclinical mastitis and its causative agents.

Prevalence of subclinical mastitis at animal (camel) level in the study area

The overall animal (camel)-level prevalence of subclinical mastitis in the study area was 76.8% (73/95) out of which 23.2% (22/95 camels) had only one mammary quarter affected, 21.1% (20/95 camels) had two quarters affected, 17.9% (17/95 camels) had three quarters affected while 14.7% (14/95camels) had all the four quarters affected.

According to divisions, subclinical mastitis at animal level was highest in Kongelai division (100% (14/14)) followed by Kasei division (82.6 % (19/23) then Kacheliba division (80% (8/10)). The lowest prevalence was in Konyao division at 0% (0/2) prevalence as shown in Figure 4 below.

Figure 4. Prevalence of subclinical mastitis at animal (camel) level per division
Prevalence of subclinical mastitis at quarter level

Out of the 380 quarter samples cultured for bacteria, 44.5% (169/380) tested positive for subclinical mastitis giving a prevalence of quarter-level mastitis at 44.5% while the rest 55.5% (211/169) of the samples tested negative (Table 2).

Table 2. Prevalence of subclinical mastitis at quarter level

Quarter

Quarter

Positive

Negative

Total

Prevalence
 (%)

Right

Fore quarter

43

52

95

11.3

Right

Hind quarter

46

49

95

12.1

Total

89

101

190

23.4

Left

Fore quarter

40

55

95

10.5

Left

Hind quarter

40

55

95

10.5

Total

80

110

190

21.1

The results showed that the right quarters were more affected compared to the left quarters with a prevalence of 23.4% (89/380) and 21.1% (80/380) for right and left quarters respectively.

The results further showed that the RHQ was the most frequently infected quarter at a prevalence of 27.2% (46/169) followed by the RFQ at a prevalence of 25.4% (43/169) (Figure 5).

Figure 5. Prevalence of subclinical mastitis per quarter
Bacterial Isolation Analysis

The bacteria isolated from the 380 quarter samples were as shown in Table 3 and Figure 6 below. A total of 114 bacteria were isolated with the most predominant bacterium being Staphylococcus aureus with prevalence of 36.0% (49/136) followed by Escherichia coli with prevalence of 27.2% (37/136). Streptococcus agalactiae and Staphylococcus epidermidis were the third predominant isolates with prevalence of 9.6% (13/136) each. Micrococcus spp & pseudomonas were the least isolates with less than 1% prevalence. A diagnosis of ‘no bacterial growth’ was made in 22 cases which is 16.2% (22/136). There were no contaminated samples recorded. Overall all milk samples produced mixed types of bacterial growth in the primary cultures. This indicated that there was a multiple infection of the quarter

Table 3. Bacterial isolation rates and their prevalences

Micro-organism

Total number of
Isolates (n)

Prevalence
(%)

Nil (no growth)

22

16.2

Staphylococcus aureus

49

36.0

Streptococcus agalactiae

13

9.6

Escherichia coli

37

27.2

Staphylococcus epidermidis

13

9.6

Micrococcus species

1

0.7

Pseudomonas

1

0.7

Contaminated

0

0

Total

136

100



Figure 6. Bacterial isolation rates and their prevalences


Discussion

The observed milking frequencies practiced by the Pokot herders in this study were in agreement with earlier studies in Kenya by Schwartz and Dioli (1992) which indicated that milking frequencies depends on season, yield and stage of lactation, the availability of alternative food and the sex and the health of the calf. McGovern (1995) reported that in times of wet seasons the Pokot people milk their camels up to 4 times a day (morning, noon, evening and night), but in dry seasons the frequency is reduced to a single milking at night only.

The high overall prevalence (44.5 %) of bacterial isolates from apparently normal camel milk samples indicated a high percentage of subclinical mastitis in camels in West Pokot County. However, the present finding from this study was con­sistent with the findings from Woubit Salah et al. (2001) who reported high preva­lence (51 %) of mastitis in dromedary camels in Borena areas of South-Western Ethiopia.

The most predominant bacterium isolated from this study wasStaphylococcus aureus with prevalence of 36.0% followed byE. coli with prevalence of 27.2% andStreptococcus agalactiae & Staphylococcus epidermidis at 9.6% prevalence each. This finding is in agreement with other findings from Eastern Sudan by Obied et al., (1996), Ethiopia (Workneh et al., 2002; Kerro and Tareke, 2003; Biffa et al,. 2005 and Almaw et al., 2008) and from Kenya by Younan et al., (2001) who reported that Staphylococcus aureus and Streptococcus agalactiae were the most common causes of camel mastitis. It has also been reported in Kenya (Maina, 1984, Omore, 1997) that Staphylococcus aureus was the major cause of subclinical mastitis in bovine (63%). As was also described by Younan et al. (2001), the prevalence of Staphylococci varies according to different studies, but there is nearly no publication on bacteriological hygiene of milk where Staphylococci are not mentioned (Eberlein, 2007).

The prevalence of E. coli has been reported by other authors to be between 1.0 and 17.3 % in samples taken from healthy camels (El-Jakee, 1998; Abdel Gadir et al., 2005). Therefore the prevalence of E. coli from this study is higher than what has been reported earlier in other studies.

The results further showed that there was cross infection from different quarters of individual camels and from camels within the same herd because identical pathogens were isolated from them. The above suggested that there was strong probability of direct transmission by the milkers from one camel to another through poor milking procedures.

Given that consumption of raw camel milk is a common occurrence among camel keepers in Kenya, the results from this study have indicated the importance of pasteurization of camel milk before consumption since potentially infective bacterial agents were isolated.

Most of the bacteria isolated in this study were gram-positive cocci. This finding is in agreement with what was reported previously by Obied et al., (1996) and Woubit et al., (2001).

The results also indicated that the most affected quarters were the right quarters with high prevalence of 48.4% in the right hind quarter (RHQ) and 45.3% in the right fore quarter (RFQ). This suggested the likelihood that in most cases during milking, the calf was left to suckle the left quarters and the right quarters were milked by the owners and due to poor hygienic milking procedures these quarters were at a higher risk of getting infected.

The results further showed that the Pokot commonly keep camels together with other livestocks such as cattle, sheep and goats. During milking of the livestock, it was observed that the camels were the last to be milked therefore there was a high possibility of direct transmission of mastitis pathogens from other species of livestock to the camel. It was also noticed during this study that camel herders (mostly young boys) kept on milking camels throughout the day during grazing. This practice might have also contributed to the higher transmission rates of camel mastitis among camels in the same herd. Frequent milking and suckling by the calf keeps flushing the mastitis pathogens out but some studies have shown that it is the major cause of mastitis in camels (Obeid et al., 1996; Abdurahman, 1996).

The results also showed that most Pokot pastoralists were using various traditional herbs to manage camel mastitis. This is consistent with what has been observed elsewhere as reported by Bornstein, (1993) and Hussein, (1993) who reported that pastoralists use various traditional (ethno-veterinary) practices to treat sick camels in Ethiopia.


Conclusions


Acknowledgements

This study was supported by ASAL-Based Livestock and Livelihood Support Project (ALLPRO). We thank the camel keepers for allowing us to access their camels.


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Received 7 July 2016; Accepted 15 February 2017; Published 1 April 2017

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