Exposure of abattoirs workers to rift valley fever virus infection in Southwestern Saudi Arabia

doi:10.4236/ojpm.2013.31004

Paper Menu >>

Journal Menu >>

Vol.3, No.1, 28-31 (2013) Open Journal of Preventive Medicine

http://dx.doi.org/10.4236/ojpm.2013.31004

Exposure of abattoirs workers to rift valley fever

virus infection in Southwestern Saudi Arabia

Tarik A. Al-Azraqi1, A wad A. El Mekki2, Ahmed A. Mahfouz3*

1Departments of Internal Medicine, College of Medicine, King Khalid University, Abha, KSA; [email protected]

2Departments of Clinical Microbiology, College of Medicine, King Khalid University, Abha, KSA;

[email protected]

3Departments of Community Medicine, College of Medicine, King Khalid University, Abha, KSA;

*Corresponding Author: [email protected]

Received 25 October 2012; revised 27 November 2012; accepted 5 December 2012

ABSTRACT

Objective: To measure seroprevalence of Rift

Valley Fever virus infection among abattoirs

workers in Southwestern Saudi Arabia. Materials

and Methods: Abattoirs in the region (Jazan,

Aseer and Al Qunfuda) were visited. Veterinari-

ans and butchers were studied. Blood samples

were then taken and tested for RVF-specific IgG

and IgM (ELISAs). Results: The present study

included 62 abattoir workers. None of whom

tested were positive for RVF specific IgM. The

overall prevalence of RVF IgG among butchers

reached 8% (95% CI: 1.3 - 75.8). Among the 31

Bengali butchers 3 were RVF IgG positive giving

a prevalence of 9.7 % (95% CI: 2.0 - 25.8), while

among four Saudi butchers one was RVF IgG

positive (25%, 95% CI: 1.3 - 75.8). Conclusions:

The study documented the lack of recent RVF

activity among abattoirs workers. High-risk, oc-

cupationally exposed abattoir workers represent

a useful sentinel population for surveillance of

RVF, especially in the absence of clinical dis-

ease.

Keywords: Rift Valley Fever; Sero-Epidemiologic

Studies; Abattoirs; Saudi Arabia

1. INTRODUCTION

Rift valley fever virus infection (RFV) outbreaks have

been reported in the southern region of Saudi Arabia

[1,2]. By the end of the outbreak (22 September 2001)

the total number of hospitalized cases amounted to 884

of whom 843 were laboratory confirmed [3]. No RVF

outbreaks or human cases have been reported in the

Kingdom of Saudi Arabia since then.

Slaughterhouse work involves stressful and tiring

tasks. Those workers suffer from serious occupational

injuries and health problems including musculoskeletal

disorders, zoonoses, skin conditions and injuries related

to animals and sharp instruments. Studies in developed

countries showed that abattoir workers are generally low-

skill staff have no control over their job tasks and may

not be aware of the determinants affecting their health

[4].

The objective of the work was to estimate seropreva-

lence of Rift Valley Fever virus infection among abattoir

workers in Southwestern regions of Saudi Arabia.

2. MATERIALS AND METHODS

2.1. Study Area

The study area (Figure 1) included Jazan, Aseer re-

gions and Al Qunfuda area in the Makkah region. Jizan

area is located in the southwest of Saudi Arabia, border-

ing the northwestern region of Yemen. The Aseer region

is located in the southwest of Saudi Arabia The region

extends from the high mountains of Sarawat to the Red

Sea, and lies few kilometers from the northern border of

neighboring Yemen. The Aseer region is bordering Jazan

and is located to its northeast. Al Qunfuda is a further

northward extension of this coastal plain in the Makah

region [5].

2.2. Study Population

Abattoirs within the study areas were identified.

Communication with preventive sectors in the concerned

directorate of health affairs and local municipalities were

made. Letters of approval (explaining the objectives of

the project and asking for their consent and cooperation)

were given to each abattoir director to ensure full coop-

eration. During late 2008 and through a series of field

trips, abattoirs were visited. Workers (Veterinarians,

butchers and clerks) present during the visit were in-

cluded in the study. Informed consents were obtained

from each individual to be included in the present study.

T. A. Al-Azraqi et al. / Open Journal of Preventive Medicine 3 (2013) 28-31 29

Figure 1. Map of Saudi Arabia showing the study area; Jizan, Aseer and Al Qunfuda area.

2.3. Blood Sampling

About 5 - 10 ml venous Blood samples in plain tubes

were taken from each participant and were allowed to

clot at room temperature (range 18˚C to 20˚C). Samples

were then centrifuged at 10,000 rpm for 10 minutes and

the separated sera were alliquotted into 2 portions and

stored at −20˚C until transported in Styrofoam boxes

containing dry ice (solid carbon dioxide, −40˚C) to the

Virus Lab of Abha college of Medicine. All samples

were received there in a frozen state, and were grouped

by the area of collection and stored in classified boxes in

deep freezers at −20˚C.

2.4. Serologic Tests

Testing of Sera for RVF-Specific IgG and IgM

Antibodies

RVF kits were provided as bulk reagents to be further

processed prior to testing. The kit “RVF IgG ELISA”

(Batch # 2007-11), is manufactured, standardized and

provided by the National Institute of Communicable

Diseases, Special pathogens Unit, Johannesburg, South

Africa. All relevant reagents were supplied with the kits

including the controls. RVF-specific IgM assays were

performed utilizing kits from the supplier mentioned

above (RVF IgM ELISA, Batch # 2007-11). The manu-

facturer’s protocols were strictly followed in performing

and evaluating the results.

2.5. Statistical Analysis

Data were coded, validated and analyzed using SPSS

PC + version 13 software package. Frequency, percent-

age, arithmetic mean, median, mode and 95% confidence

intervals of the estimate were used to present the data.

3. RESULTS

3.1. Description of the Study Sample

The present study included 62 persons working in ab-

attoirs in the study regions (Table 1). They included 50

butchers (80.6%), 10 veterinarians (16.1%) and 2 clerk

workers (3.3%). Their age ranged from 19 years to 60

years with an average of 36.77 ± 10.29 years and a me-

dian of 35 years. The majority of butchers were Bengali

(31.62%), followed by Indians (5.10%), Saudis (4.8%)

Sudanese (4.8%) and Egyptians (3.6%). Veterinarians

T. A. Al-Azraqi et al. / Open Journal of Preventive Medicine 3 (2013) 28-31

Table 1. Seroprevalence of RVF IgG among the study sample of abattoirs workers in Southwestern Saudi Arabia (N = 62).

Variables No. Examined % No. Positive Prevalence (%) 95% Confidence Interval

Occupation Group

Butchers

Veterinarians

Clerks

TOTAL

Nationality of Butchers

Saudi

Bengali

Indian

Sudanese

Yemeni

Egyptian

TOTAL

80.6

16.1

3.3

100

6.5

9.7

2.8 - 17.4

1.8 - 15.7

1.3 - 75.8

2.0 - 25.8

were mostly Egyptians (8.80%) and Sudanese (2.20%).

The clerks were Saudis. The period of stay of non Saudis

in slaughter houses ranged from 3 year to 35 years with

an average of 10.38 ± 7.24 years and a median of 8 years.

The majority of workers (39, 62.9%) had no complaints

at all in the six months period prior to the survey. The

most frequent complaints were back pain (9, 14.5%) fol-

lowed by headache (4, 6.5%).

3.2. Sero-Prevalence of Rift Valley Fever

Virus Infection

3.2.1. Seroprevalence of RVF-Specific IgM

None of the 62 samples tested for Rift Valley Fever

IgM, were positive giving a Seroprevalence of zero %.

3.2.2. Seroprevalence of RVF-Specific IgG

Out of 62 samples tested for Rift Valley Fever IgG,

four samples were positive giving a Seroprevalence of

6.5%. The prevalence of RVF IgG among butchers

reached 8%. On the other hand, the prevalence among

veterinarians and clerk workers was zero percent. Among

the studied four Saudi butchers one was positive (25%).

Among the 31 Bengali butchers 3 were positive giving a

prevalence of 9.7%. On the other hand, none of the stud-

ied Egyptian, Sudanese and Indian butchers was found

positive. The study showed that the 4 positive cases of

Rift valley Fever IgG had no complaints at all in the past

6 months.

4. DISCUSSION

Abattoir workers and herdsmen are at a high risk of

acquiring RVF virus infection [6,7]. Among butchers in

the studied abattoirs, the RVF IgG seropositivity rate was

8%. This figure is higher than the overall seroprevalence

of 6.0% among community based general population

found in a recent study in the same region [8]. A sero-

prevalence figure of 7.3% was found among abattoirs

workers in Tanzania in 2004 before 2007 epidemics [9].

A higher rate of 40% has been documents among abattoir

workers in Kenya [7]. Again the higher rate in the Ken-

yan study could be attributed to cumulative previous

exposures to RVF virus. Interestingly, the seropositive

abattoir workers were all butchers, among whom the

seropositivity rate was 8%. This variability in prevalence

may also be explained by mere chance. The seropositive

butchers were a Saudi and three Bengalis and were resi-

dents of the study region during the outbreak of 2000-

2001. Only the Saudi recalled the fact that he was diag-

nosed as a case of RVFV infection and most likely the

remaining 3 were subclinically infected during the out-

break and none of the rest of the abattoir workers gave a

history of any illness during 6 past months. This argu-

ment is probably true since the entire sero-negative abat-

toir workers were appointed after the outbreak of 2000-

2001 and none of them was positive for RVF-specific

IgG or IgM thus ruling out any evidence of previous ex-

posure or recent infection.

While it is difficult to segregate slaughterhouse activi-

ties involving exposure to animal tissue, findings during

the 1993 outbreak in Egypt demonstrated that those tasks

with highest exposure to animal blood, i.e., cutting ani-

mals' throats and handling animal parts, were associated

with increased risk of infection with RVF virus. This

provides further evidence that direct contact with poten-

tially infected animals is a prominent mode of transmis-

sion of the virus [10].

The results of the present survey suggest that high-risk,

occupationally exposed abattoir workers represent a

useful sentinel population for surveillance of RVF, espe-

cially in the absence of clinical disease. Abattoir workers

in the study regions must adhere to protective measures.

T. A. Al-Azraqi et al. / Open Journal of Preventive Medicine 3 (2013) 28-31 31

The present study documented a high prevalence of

RVF-specific IgG among those workers compared to the

general population. These protective measures should

include the wearing of masks, gloves, aprons and other

protective barriers. Regular use of soap, water and anti-

septics on exposed body parts should be encouraged

during their practices. The researchers observed the lack

of regular adherence of abattoir workers to these protec-

tive measures. More comprehensive training program in

the region for abattoir workers is needed. A recent study

in Portugal among butchers affirmed education as an

important link to the two variables: knowledge and atti-

tudes; customs and environment in abattoirs [11]. The

training programs for abattoirs workers in the region

should incorporate activities that support skills develop-

ment relevant to real life situations in which the workers

can put information into practice. There is a need to de-

velop training methods that proved to change behavior as

well as imparting knowledge.

REFERENCES

[1] Arishi, H., Ageel, A., Abdu, R.M., et al. (2000) Update:

Outbreak of Rift Valley fever—Saudi Arabia, August-

November 2000. Morbidity and Mortality We ekly Report,

49, 982-985.

[2] Centers for Disease Control and Prevention (2000) Out-

break of Rift Valley fever—Yemen, August-October 2000.

Morbidity and Mortality Weekly Report, 49, 1065-1066.

[3] Madani, T.A., Al-Mazrou, Y.Y., Al-Jeffri, M.H., Mishkhas,

A.A., Al-Rabeah, M., Turkistani, A.M., Al-Sayed, M.O.,

Abodahish, A.A., Khan, A.S., Ksiazek, T.G. and Shobok-

shi, O. (2003) Rift Valley fever epidemic in Saudi Arabia:

Epidemiological, clinical and laboratory characteristics.

Clinical Infectious Diseases, 37, 1084-1092.

doi:10.1086/378747

[4] Alvarado-Esquivel, C., Liesenfeld, O., Estrada-Martínez,

S. and Félix-Huerta, J., (2011) Toxoplasma gondii infec-

tion in workers occupationally exposed to raw meat. Oc-

cupational Medicine (Lond), 61, 265-269.

doi:10.1093/occmed/kqr032

[5] (2006) Health statistics year book. Ministry of Health.

Saudi Arabia.

[6] Chamers, P.G. and Swanepoel (1980) Rift Valley fever in

abattoir workers. Central African Journal of Medicine, 26,

122-126.

[7] Logan, T.M., Davies, F.G., Linchicum, K.J. and Ksiazek,

T.G. (1992) Rift Valley antibody in human sera collected

after an outbreak in domestic animals in Kenya. Tran-

sactions of the Royal Society of Tropical Medicine and

Hygiene, 82, 202-203.

doi:10.1016/0035-9203(92)90571-S

[8] Al-Azraqi, T., El Mekki, A.A. and Mahfouz, A. (2012)

Rift Valley fever in Southwestern Saudi Arabia: A sero-

epidemiological study seven years after the outbreak of

2000-2001. Acta Tropica, 123, 111-116.

doi:10.1016/j.actatropica.2012.04.007

[9] Swai, E.S. and Schoonman, L. (2009) Prevalence of Rift

Valley fever immunoglobulin G antibody in various oc-

cupational groups before the 2007 outbreak in Tanzania.

Vector Borne and Zoonotic Diseases, 9, 579-582.

doi:10.1089/vbz.2008.0108

[10] Abu, E.R., El-Sharkawy, S., Olson, J., et al. (1996) Pre-

valence of anti-Rift Valley fever IgM antibodiesin abat-

toir workers in the Nile delta during the 1993 outbreak in

Egypt. Bulletin of the World Health Organization, 76, 155-

158.

[11] Gomes-Neves, E., Cardoso, C., Araújo, A. and Costa, J.

(2011) 2011Meat handlers training in Portugal: A survey

on knowledge and practice. Food Control, 22, 501-507.

doi:10.1016/j.foodcont.2010.09.036