This study was conducted in Tanzanian’s most densely populated area with highest concentration of both pharmaceutical and commercial industries, hospitals, pharmacies and drug sellers, intense use of antimicrobials including insecticides in crop and animal farming, and intense environmental contamination (24, 25, 27, 32, 33) and is therefore certainly the hottest hotspots for the spread of AMR organisms between human, animals and environment in the country. Additionally, the Msimbazi River drains to the Indian Ocean, which is international water bodies therefore, the practice of AMU and AMR reflects wider implications.
We found a very high usage (87.6%) of veterinary antimicrobials in poultry and pig farming mostly for prophylaxis rather than treatment. The high usage might be attributed to the prolonged exposure in animal farming coupled with negligence in adhering to good hygienic practices and other biosecurity measures. The higher proportion in this study corresponds to the one reported in Sudan, Ghana, Nigeria, and Cameroon where routine antimicrobials use are the normal practices even in absence of disease outbreak (31, 34–36). Predominantly, farmers were making treatment decision based on presentation of clinical signs, which carries a high possibility of misdiagnosis, administration of inappropriate drugs and improper dosage. Similar studies in Sudan and Nigeria reported that antimicrobial use without involving veterinary practitioners and lack of laboratory findings in diagnosis of animal diseases leads to improper use of antimicrobial (31, 37).
Disturbingly, many farmers were using human medicines including amoxicillin, doxycycline, ampicloxacillin, tetracycline, chloramphenicol eye drops, ciprofloxacin, metronidazole and chloramphenicol to treat animals. Due to limited extension services and poor animal health delivery systems, farmers tend to buy veterinary and non-veterinary drugs from private drugs shops and treat their livestock themselves. There is high chance that farmers seek to maintain animal health welfare by using drugs that are cheaper, readily available, easy to use and more effective. The use of human medicine in animals proves the weakness in implementation of laws and regulation governing handling, sale and use of antimicrobials both in human and animal and limited extension services. This weakness spurs the problem of AMR organisms. This finding is consistency with (35, 38) that antimicrobial use in food animals is accompanied by lack and or weak regulation, limited veterinary services and higher costs of private veterinary consultants.
Apparently many farmers were stocking veterinary drugs at home, with a likelihood of poor handling and storage. The stocking of drugs might interfere with the active ingredient leading to reduced efficacy of the antimicrobials as reported by (39, 40). Moreover, metaphylaxis was very common, implying that even the healthy animals in a herd or flock were also treated thus escalating the chance of AMR development Similar findings was reported in Tanzania (10) that stocking of veterinary antimicrobials was associated by poor improper usage leading to drug residues in animal products.
Frequently, farmers were using a combination of veterinary drugs on advice of financially motivated veterinary drug sellers who do not have enough knowledge on drug use, side effects, proper dosage and withdrawal period taking advantage of inadequate veterinary services and extension officers. Similar findings were reported in Cameroon and Ethiopia that private veterinary services are expensive (36, 41) and the veterinary professionals are responsible for the abusive use of antimicrobials (42). We found tetracycline and quinolones being the most used antibiotics due to being cheap, readily available and accessed easily, without restrictions (12, 43), and are often sold by informal vendors at informal markets and even along the road (10, 44). Use of tetracycline in animal has been documented in Cameroon and Ghana probably since they are cheaper and has broad-spectrum activity against variety of diseases (34, 45, 46). The wide spread use of quinolone observed in this study corresponds to the one reported in the previous studies (37, 47, 48) that quinolones are widely used in animals for diarrhoea treatments and prophylactic despite the fact that they are expensive. Antibiotics are commonly sold during cattle auction days by informal vendors, such as petty traders and livestock keepers. Antibiotics found in markets like these are often unregistered, and therefore sold at very cheap prices (Abdu Hayghaimo- Former director of Veterinary services in Tanzania, personal communication, April 1, 2013). The quality of these medicines is undetermined.
We found many farmers to be aware of withdrawal period, but most of them were not implementing it for several reasons including i) economic loss ii) regulatory bodies in Tanzania have not yet set withdrawal periods for veterinary drugs and farmers rely, primarily, only on veterinary drug sellers. As a result, farmers rarely comply with the recommendations and the responsible regulatory authorities do also not monitor usage. Consequently, veterinary drug residues are likely to be present in food of animal origin, which poses a potential hazard to human health (49). Failure to observe withdrawal periods in animal has been reported in Tanzania, Nigeria, Ethiopia, Sudan and Malaysia that it was among the reason for antimicrobial residues in food of animal origins and propagates development of antimicrobial resistance (10, 12, 39, 50–52).
Additionally, our survey found different types and brands of antimicrobial used were from different sources that are not monitored and controlled. In Tanzania, the quality and quantity of veterinary antimicrobials are difficult to assess. This finding is comparable with the one reported by (31, 53) that there is variation in quality of veterinary antimicrobials which is in tandem with insufficient system for monitoring of antimicrobial use in animal production. While the Tanzania Food and Drug Authority (TFDA) perform quality assessments, on imported drugs at the port of entry, there is very weak post-market surveillance on veterinary medicines. We found the government does not control antibiotics included in animal feed and that informal feed manufacturers that are found in small kiosks do not regulate the quantity of antibiotics included, leading to unnecessary exposure to antibiotics. During focus group discussions it became apparent that frequently drug importers, distributors and wholesalers supply drugs direct to consumers.
With regard to IPC, we observed poor housing with unhygienic conditions and limited air circulation in poultry houses. This most likely facilitated occurrence of most of the reported diseases by the farmers such as respiratory infections and typhoid in poultry and intestinal worms and skin diseases in domestic pigs, prompting increased use of antimicrobial agents. Poor housing conditions are in contrary to the Animal welfare act 2008 (54) that requires animals to be kept in approved structures that conforms to the quality hygienic and management practices. Collectively our findings suggest the acute need for the availability of livestock extension services (government or regulated private) at local administrative level for the farmers to seek advice. We envisage that livestock extension personnel will be much trusted and their consultation service will be cost-effective and public health relevant, as it will reduce the magnitude of AMU in animal farming and improve the safety of short-cycle stock derived food commodity. Furthermore, we recommend strengthening of the awareness and understanding of antimicrobial resistance by farmers and community level service providers (traders, extension personnel, and community based animal health workers) through effective communication, education and training through collaboration between government and Civil Society organizations (CSO).
With regard to environmental contamination, respondents identified a number of activities taking place in the Msimbazi basin as potential drivers of AMR. These include effluents from households, hospitals, abattoirs and pharmaceutical and commercial industries, use of pesticides, flooding, and emptying of sewage into the environment during rainy seasons. Despite this, most of these activities are still on-going; posing health risks to humans and livestock by causing infections that are difficult to treat (25). This is contrary to the Environmental Management Act, 2004 (55), which provide for legal and institutional framework for sustainable management of the environment, including impact and risk assessments, prevention and control of pollution, waste management, environmental quality standards, public participation and compliance.
We found out that the existing Veterinary Acts (Code of Professional Conduct Regulations 2005, Livestock Policy 2006, Procedures for Registration Examination for veterinarian and veterinary specialists Regulations 2005, and Veterinary practice by Paraprofessionals Assistants Regulations 2005) (56–59), The hides, skins and Leather Trade Act No. 18 of 2008 (60), Veterinary Act No.16 2003 (61), Animal Welfare Act 2008 (54), and the Meat Industry Act 2006 (62) are weak and none of them specifically addresses issues of AMU and AMR in animals. Likewise, National Fisheries Policy of 2015 (63) that aims at developing a sustainable, competitive, vibrant and more efficient commercialized fisheries and aquaculture industry has no mention of AMU and AMR. We recommend that these acts and regulatory documents should be updated and work logistically to embraces a One Health approach, which is cost-effective strategy for curbing AMR. The need for a cross agency and cross-disciplinary collaborations has been suggested in some studies in Tanzania (14, 64) for the purpose of optimizing AMU, control quality, distribution, handling and awareness creation in human and animals and other related sectors.
On a positive note the government of Tanzania has developed a National Action Plan for Health Security 2017–2021 that aim to create and maintain active collaboration between the sectors for addressing health security using “One health approach concept” so as to ensure that there is timely preparedness, and a consistent and coordinated response in the event of occurrence of an event of public health concern. The plan is implemented under the guidance of the Prime Minister’s Office in order to achieve an Inter-ministerial Committee to administer the plan, and monitor and evaluate its implementation from all relevant line ministries. At the same time the government has also developed a National action plan on antimicrobial resistance (2017–2022) (65), which adopted the One Health Approach, and has strategies that are related to monitoring and surveillance of AMR and antimicrobial consumption in human and animal, improving antibiotic stewardship and control the spread of AMR in both clinical and farm settings, and increase knowledge and public awareness on AMR and establish national governance for inter-sectoral actions.
Fortunately, there are a number of research and OH AMU and AMR projects that are currently being implemented in Tanzania including i) Supporting the National Action Plan on AMR in Tanzania (SNAP-AMR) that assesses prescribing practices in different health care settings as well as investigating community access and attitudes to antibiotics among householders, community 'drug' shops and unregulated sources such as roadside traders and examine use in livestock by individuals with different levels of knowledge about AMR, e.g. district vets, community livestock officers and livestock holders ii) Fleming Fund Country Grant that aims to strengthen Tanzania’s national Antimicrobial Resistance (AMR) surveillance strategy by addressing the gaps in AMR data and strengthening antimicrobial stewardship. Ensuring that veterinary laboratories have access to a cadre of expert trainers tools, methods for analysis and interpretation and propose minimum data sets. Existing tools such as AfyaData can be adapted to collect AMR data and standardized protocols will allow for integration of data and comparative analysis among countries. These projects provide a platform for implementation of the national action plan on addressing AMU and AMR.