Occupational risks and their implications for the health of poultry farmers

1 Introduction

The poultry industry has experienced increased productivity from the use of innovative technologies. The strength of the Brazilian poultry sector lies in the quality of the process, which involves excellence in technology, genetics, handling, ambience, and health. However, such an investment would be meaningless without the dedication of the poultry worker. This professional must have basic conditions for working without impacting his/her welfare. The concept of welfare relates to physical, mental, or social health [1].

Estimates show that 2.34 million people around the world die every year due to work accidents and diseases. Of these, about 2.02 million people die from occupational diseases. Estimates also point to 160 million cases of nonfatal occupational diseases [2].

Official statistics rely on data on work accidents and diseases, that is, data on workers in the formal economy. However, these statistics do not include workers who represent the majority of the active population, such as rural workers and workers in small and medium-sized enterprises and in the informal economy. These workers, invisible to statistic annuals, face high levels of risk and remain outside the systems for prevention, notification, and compensation of occupational diseases [2].

Poultry activity contributes to this problem, as it exposes workers to accidents and unhealthy conditions with physical, chemical, biological, and ergonomic risks, not to mention psychological and organizational factors [3, 4]. Poultry workers expose themselves to varied risks; notwithstanding, the Brazilian standard that deals with unhealthy activities and operations (NR-15) do not include these professionals. NR-15 defines unhealthy factors and the tolerance limits on exposure to occupational risks not including poultry activities [5].

In view of the importance of worker health and welfare for good results in the poultry sector, we list risk factors in poultry farms. In this sense, we analyze operational, behavioral, and environmental aspects, and estimate the prevalence of symptoms in poultry farmers.

2 Material and methods

We evaluated poultry workers through quantitative and qualitative analysis, and collected data through nonprobabilistic convenience sampling. The data collection instrument was a semistructured online questionnaire (Survey Monkey and Google forms) containing 58 questions to investigate risk factors in the workplace and their implications on health, through a list of possible health problems. The questionnaire, adapted from [6], consists of questions about sociodemographic, environmental, and professional characteristics of the interviewees, according to the Brazilian regulatory standards [7, 8] NR-9 and NR-17. To assess the risk of musculoskeletal injury, we used the Nordic Musculoskeletal Questionnaire, adapted by Barros and Alexandre [9].

The data collection period was from May to December 2018. We obtained 80 completed questionnaires, from five regions of Brazil. We individually approached 1,099 poultry farmers, allowing only one subscription per mobile Internet Protocol (IP) address to prevent duplication of responses. Although the response rate was considered low in relation to the number of questionnaires sent, 80 responses were quite satisfactory by the authors. All participants signed an informed consent form before enrollment.

3 Results

Of the poultry farmers interviewed, were 80%men and 20%women; 62%were less than 40 years old; 85%were in a stable or marital relationship; and 53%had an average educational level.

Regarding poultry systems, 47%of the interviewees worked in air-conditioned houses; 44%in dark houses; 37%in conventional houses; 17%in semiclimatized houses; and 46%worked in more than one poultry system simultaneously.

Regarding the ventilation of the working environment, 15%of respondents claimed to work in environments with natural ventilation, and 85%in environments with mechanical ventilation. The majority of respondents (61%) worked in a totally closed environment, while 39%worked in an open or semiopen environment.

As for lighting, 64%of respondents worked in artificially lit environments, and 24%worked in environments with illuminance between 1 and 10 lux (Table 1). Regarding occupational profile, 32%of respondents reported working as poultry farmers for at least 5 years, and 24%worked in this area for more than 20 years. Of the farmers surveyed, 90%work on both shifts and 10%on the day shift. Regarding weekly workload, 85%claimed to work more than 40 hours, without, however, measuring overtime. As for employment bond, 85%are owners and 15%are hired employees.

As for the incidence of accidents, 61%of workers claim to have suffered some type of accident with health consequences in their current work. Of these, electric shock (10%) and musculoskeletal injuries (10%) are the most frequent, followed by falls and burns, both with 8%of occurrence (Table 2).

Regarding the use of personal protective equipment (PPE), 34%of workers claimed to rarely or never use it. Among the most used PPE are boots (76%), mask (59%), gloves (39%), and goggles (36%) (Table 2).

Of the interviewees, 88%live with their families on the same property on which they work. Regarding health problems, 41%of poultry farmers felt unable to perform their activities at some time, 17%claimed to have had spinal disorders, 8%had influenza, and 5%reported poisoning. Fall injury, sharps injury, hernia, depression, bacterial infection, knee injury, and shortness of breath each accounted for 2%of the health problems in this population. Moreover, 25%of respondents claimed to make frequent use of medications.

Regarding physical risks perceived by poultry farmers, 64%of respondents were injured while handling ovens, furnaces, and wood-burning heaters, followed by intense heat (39%), excessive humidity (31%), and noise (27%) (Table 3).

As for exposure to biological risk factors, most respondents reported handling dead animals (61%), sick animals (59%), and animal waste (44%) (Table 3).

Among chemical risks, 71%of poultry farmers reported exposure to unpleasant and harmful dust. Moreover, 64%of workers reported intense ammonia odor, and 44%reported using harmful chemicals and/or hazardous materials, equaling the number of workers who reported inhaling substances while handling animals (Table 3).

Regarding accident risks, 63%of workers point out electric shock, followed by burns (59%) and exposure to heat sources (53%). Only 10%indicated low light as an accident risk, and 5%considered the light in the working environment to be inadequate, not meeting the minimum amount of light required for the work to be performed. None of the respondents reported excess light as a problem among the observed issues (Table 4).

Regarding ergonomic risk, 64%of workers reported working for more than 8 hours a day, followed by poor body posture during work (44%) (Table 5).

Among the organizational and psychosocial risk factors, low remuneration for the activity performed stood out with 63%, followed by excessive workload (53%) (Table 5).

Regarding other health implications, stress (46%) and spinal disorders (44%) stood out as the main complaints, followed by sleep disturbance (34%), respiratory disorders (29%), and frequent headaches (27%) (Table 6).

No respondent had repetitive strain injury (RSI), work-related musculoskeletal disorder (WRMD), fertility problems, frequent absences due to health problems, heart disease, cancer, liver disease, or alcoholism.

When separating poultry farmers by characteristics of the work environment (facilities), those who worked in open or semi-open houses had a higher frequency of spinal disorders (22%), respiratory disorders (14%), stress (15%), use of medication (14%), and sleep disturbance (12%). Those who worked in closed poultry houses showed higher prevalence of symptoms, in which the following health problems stood out: stress (31%), spinal disorders (22%), frequent headaches (22%), sleep disturbance (22%), muscle pain (20%), respiratory disorders (15%), mood and behavioral changes (17%), family problems (14%), eye problems (14%), frequent use of medication (12%), varicose veins (12%), limb numbness (12%), and digestive problems (10%).

Regarding the global responses obtained with the questionnaires, it is important to highlight a low response rate was expected result, poultry professionals have little familiarity with this type of research, so a large number of questionnaires was sent so that even with the aforementioned limitation, it was possible to obtain a satisfactory number of responses. In addition, because it is a relatively extensive questionnaire and does not have any compensation for filling it out, such as prizes, sweepstakes or donations, it is possible that the response rate may be lower [10]. The number of responses considered adequate was reached and it was possible to interpret the results of the present research.

Most poultry farmers claimed to work under mechanical ventilation, which favors exchange of air in closed environments, making them suitable for human presence. Air renewal dissipates heat and gases such as ammonia and carbon dioxide, reduces smoke, dust, moisture, and odors [11, 12], provided that it is performed routinely.

Anthropogenic spaces need abundant light, and natural light stands out as it allows spatiotemporal perception, essential to the functioning of biological clock. In turn, artificial light extends anthropogenic activities at times and places where natural light is absent or insufficient [13], directly interfering with eye functioning and the physiological mechanism of vision [14].

During long periods of exposure to artificial light or in low light environments, the circadian system is not properly stimulated by solar radiation and melatonin production is deficient [14]. This can cause visual fatigue, headache, and irritability, in addition to work errors and accidents [13]. However, the illuminance level for broilers in dark houses should be only the necessary for birds to reach the feeders and drinkers. This level corresponds to 30–40 lux in the first weeks of the animals’ life, and 5 lux in the other life stages [15].

More than half of the interviewees worked under artificial lighting, with up to 10 lux of illuminance, the minimum illuminance threshold for continuous work is 500 lux incident on the retina, which can mean up to 1000 lux incident in the environment [16].

The use of personal protective equipment is essential for work safety. The poultry worker faces chemical, biological, and physical risks; thus, PPEs are essential to reduce accidents. The studied poultry workers often neglected these equipment, even knowing their importance. When observing the main risks evidenced by workers in this research, we can consider boots, masks, gloves, and goggles as the main PPEs for the reduction of accidents within poultry farms. Absence or misuse of PPEs relates directly to the main complaints of diseases of rural workers [17].

As we also verified in this study, most poultry workers live close to rearing facilities. This can benefit workers by reducing their commuting to the workplace, but it can also imply risks to human health. Rasamiravaka et al. [18] addressed the existence of homes near the workplace and concerns about employees sleeping and having meals close to animal housing facilities, this could generate risk factors associated with oral and/or nasal contamination by Staphylococcus aureus.

Activities involving heat sources can be considered an important physical risk from the point of view of occupational health, as mentioned by significant number of interviewees. When the worker exposes himself/herself to a heat source and receives more heat than the organism is capable of dissipating, the following consequences can occur: heat exhaustion, dehydration, heat cramps, thermal shock, low blood pressure, reduced blood volume, cramps due loss of water and minerals impairing the functioning of tissues and organs [19].

One-third of the workers also reported relative humidity levels inside the poultry houses as a factor of discomfort at work. Plate evaporation and/or nebulization are common practices that reduce temperature and simultaneously increase the relative humidity of the environment [13]. These practices can lead to a relative humidity above 60%, contributing to contamination by pathogenic microorganisms and bioaerosols [20]. Moreover, they indirectly influence the incidence and prevalence of allergic diseases [21], infection by Salmonella and Eurotium spp. [23], and viral diseases such as influenza [24]. A good ventilation rate is thus necessary to minimize these negative effects of high humidity, avoiding the accumulation of water vapor [13].

The interviewees mentioned noise intensity less often compared to relative humidity. Bett et al. [25] state that the maximum noise found in poultry houses was 74 dB. This level does not exceed the tolerance limits, since the level allowed by Brazilian regulators for humans is up to 85 dB for 8 hours of work. Notwithstanding, levels above 80 dB require ear protection.

Biological risks were prominent in the responses since these workers are in constant contact with air contaminants (bioaerosols), besides handling sick and/or dead animals. The poultry activity can thus be characterized as an unhealthy activity. These workers are at risk of developing infectious diseases, allergies, or toxicity due to the presence of living organisms such as bacteria, viruses, fungi, or parasites [26].

Regarding chemical risks, dust concentrations in poultry houses had higher levels of total endotoxins than flower production facilities and pig farms, as well as higher levels of ammonia and carbon dioxide [23]. Tasks performed throughout the broiler growth cycle result in a large amount of dust in the environment [27]. Consequences include increased presence of organic and inorganic dust, ammonia, microorganisms [28], microbial components, and hydrogen sulfide, which can irritate the eyes and/or act on the human nervous and respiratory system [29, 30].

Dust concentration increases in the final stage of broiler growth due to accumulation of excreta and feather debris [31]. This relates directly to greater inhalation by workers, thus leading to more complaints. According to [27, 33], activities inside the poultry houses can induce respiratory allergic reaction in workers and decrease lung function during a work shift [34–37].

Air renewal is necessary in closed poultry houses to maintain air quality. However, the activity does not remove part of the air, which is only diluted but not simultaneously exhausted. Equipment dimensioning must meet system maintenance needs, avoiding the increase of chemical pollutants such as ammonia, carbon monoxide and dioxide, and biological agents such as fungi, bacteria, and mites, due to the low rate of air renewal [38]. Thus, indoor air pollution can easily affect worker health, welfare, and productivity [39].

The main factors of occupational stress may relate to the administration sector, the work system, the quality of human relations, and work organization. The prominent factors in this study were excessive workload, insufficient salary, incompatibility between work and rest cycles, unhealthy working conditions, and psychosocial risks. This may lead to physical and psychosocial consequences, affecting professional performance [40]. Many workers in this study reported medication use demonstrates that workers are not in their full health, which may indicate that they are subjected to situations that affect their well-being, causing unwanted symptoms that need to be remedied with the use of medications, as well as inadequacies in the work environment.

The relationship between work and family problems can be considered a psychosocial risk because work demands lead to family conflict, often due to long hours of work. In addition, the lack of contact with family members alters social life, transforming the poultry into an alienated, angry, and stressed individual [40].

The activities performed by poultry workers inside the poultry houses include moderately heavy physical load in facilities where the equipment requires manual handling. This leads to shoulder, elbow, back, hip, knee, and ankle injuries [41]. Poultry farmers in the present study reported that these injuries usually occur in the form of musculoskeletal pain and discomfort. According to [27], musculoskeletal pain in the lower back relates mainly to the activities of filling and cleaning feeders and handling feed carts. These activities present a high risk of injury to the spinal vertebrae, especially when there is a need to pull and move the feed cart, evidenced by the weight of the load [4]. In addition to these activities, revolving the bed with the aid of a hoe and a wooden trident negatively affects the worker’s posture [4].

Complaints of excessive workload and working for more than one shift also stood out in this study. These factors negatively interfere with the necessary rest period for workers to recover from their work activities and to be able to resume them on following days. In this sense, the quality of sleep is fundamental because its reduction can lead to depression and impair alertness, causing accidents [42].

In a general context, the physical and psychosocial complaints mentioned by poultry workers resemble sick building syndrome. In 1982, the World Health Organization defined sick building syndrome as the presence of symptoms such as headache, fatigue, lethargy, burning eyes, irritation of mucous membranes, skin abnormalities, and lack of concentration [43]. Health professionals consider these symptoms after ruling out other possible causes [44]. Most of these symptoms occurred frequently in the present study as a function of the rearing system, facilities and technologies used in the poultry farms, and indoor microclimate.

5 Conclusions

The exposure of poultry farmers to unhealthy environments often leads to symptoms such as stress, headache, eye and mucous membrane disorders, respiratory disorders, back pain, depression, muscle pain, and symptoms associated with sick building syndrome. It is essential to strengthen the importance of the mandatory use of PPE for these workers, including respirators, goggles, safety gloves, PVC boots, skin protection creams, and PVC apron.

Therefore, the present study points to the need for financial, legal, and informational investments by the state, agroindustries, and associations. These entities must carry out programs to improve the health of poultry farmers, not only to maintain physical and psychological health, but also to reduce occupational accidents and draw attention to the occupational risks presented.

Conflict of interest

No potential conflict of interest was reported by the authors.