Health implication of rodents’ infestation on man and its environment   

Introduction

Rodent is any of the relatively placental mammals, having constantly growing incisor teeth specialized for gnawing. The group includes porcupines, rats, mice, squirrels, marmot etc. The word rodent infestation in surrounding can prove extremely destructive. Different species are known for different nesting and feeding behaviours, but infestation cause damage to gardens and yards as well as to the home (Orikinlle, 2015).

According to Factmaster (2014) “rodent infestation is a harassing or troublesome invasion of rodent”. Similarly the Merriam-Webster (2014) defines rodent infestation as the actual organisms living on or within a host.

According to Food Standards Agency (2013), three food businesses in Hull City have been forced to close because they were infested with rats. Which when public health had been placed at risk by the filthy conditions they founds which lead to the magistrates issued orders during February to stop trading at a takeaway. A fish processor and a home delivery firm all based in Hull City council officials said it was highly unusual for three premises to be closed in such a short space of time. The takeaway was closed after environmental health officer found rat droppings and food left exposed to contamination by vermins posing an imminent risk to public health.

Belfast (2009) published that a dead mouse was found in the bread after a customer bought the loaf in bally money area centered for disease control and prevention (CDC) (2014) listed some disease transmitted by rodents such as Hantavirus, Haemorrhagic fever, toxoplasma, etc., apart from disease transmission, rodents infestation also have severe economic implications.

According to Tobin and Fall (2004, as cited in Almeida, 2014) initial estimates by United Nations (UN) in 1982 indicated that rats alone destroyed 42 millions of tons of food worldwide that was worth 30 billion dollars. They also cause structural damage too.

Herwing (2006) observed that rodent are involved in the transmission of more than 60 infectious diseases like leptospirosis or weils disease, salmonellosis, tularemia, lymphocytic choriomeningitis (LCMV) to humans through a number of pathways, some are direct such as rat bite or humans eating infected rat meat. Others more indirect through spoiling of food with infected rodent excreta, pathogens excreted in the environment and later inhaled or ingested by humans or penetrating the human skin or pathogens that are transmitted by ectoparasites.

Conceptual framework

There are more than 1,700 species of rodents, the most common are the brown rat (Rattus Norvegicus), the black rat (Rattus Rattus) and the house mouse ( Mus Musculus) are serious pests, eating and spoiling food stored by humans and spreading of disease (Wagoner,2014). Given the diversity of rodent it is important that species are correctly identified if their role in the epidemiology of disease is to be understood. The global burden of rodent borne diseases is difficult to calculate because they are often under-diagnosed. In addition to the health cost, there is also the economic cost that a country may face when affected by disease that affect its international trade position (Herwing, 2006).

Commensally rodents

This is domestic rodent that lives in close association with human being. They are nocturnal and tend to move in doors to warmer areas during late, fall or early winter (June to August) and return to the outdoors in lake spring where suitable harbourage is available. Commensally rodents generally have poor sense of vision, but they have acute sense of small touch and taste. They tend to gnaw any material that is softer than their enamel and they are generally good climbers, jumpers, and burrowers. The three (3) species of commensally rodents are; the roof rat, the Norway rat and the house mouse (Olorunda, Ukah & Onojeharho, 2009).

1. Rattus rattus (roof rat)

Rattus rattus is the technical name for the roof rat. It is also called the black rat or tree rat. It is very slender and agile and its tail is longer than the head and body combined. Its total length ranges between 12 to 17 inches and can weigh up to about ¾ of a pound. Roof rat nests above ground and lives on ivy, wild blackberry vines, attics garages and wood piles. It will enter building if given the opportunity and often use utility lines and fences as runaways. It prefers to feed on fruits, nuts, ivy and pet food commonly found in residential areas.

2. Rattus novengicus (Norway rat)

Rattus Novengicus also known as Norway rat, sewer rat, or wharf rat it is larger than the roof rat. It has smaller eyes and ear than the roof rat and its tail is shorter than the combined head and body length may reach 18 inches and may weigh up to over 1 (one) pound. Norway rat lives and nests in underground burrow system and waterfronts under blackberry vines, under wood piles. It feed on garbage, pet food meat scraps, cereal grains, fruit and vegetables (Olorunda, Ukah & Onojeherho, 2009).

3. Mus musculus

Mus musculus is also known as the house mouse. It is small, slender bodied and the tail is longer than the length of its head and body. Its body size ranges from 2^1/₂ to 3^4/₅ inches long. Its body color is generally grayish brown with a gray or buff. Belly. House mouse is agile climber and can fit through openings as small as ¼ inches in diameter it eat may types of food but prefers feeds and grain. It normally travels an area averaging 10 to 30 fit in diameters.

Table 1: Characteristics of different species of rodents  

(Source: Olufemi, 2009).

Causes of rodent infestation

The following are some of the causes of rodent infestation in the bakery.

• Indiscriminate dumping of refuse/dirty environment
• Overgrown weeds in the environment
• Unprotected doors and windows
• Left over foods etc.

1. Indiscriminate dumping of refuse

Halimah (2015) stated that waste and food scraps disposed in trash cans that are not tightly closed is the main cause of rodent infestation at markets and bakery’s, food courts and recreation areas, urban well being, housing and local government deputy minister Datuk Halimah Mond coteries said waste dumping in the streets near catteries’ and failure of food traders to ensure cleanliness and hygiene at their stalls also attract the rodents. Also said refuse placed in plastic bags but not placed in a properly covered bin also attracted the rodent.

2. Overgrown weeds in the environment

When there is presence of overgrown weeds around the bakery, it aids rodent infestation because overgrown weeds serve as inhabitant for the rodents to thrive well, thereby increasing their numbers. When such rodents finally gains entrance into the bakery premises, it causes severe damage and loss, spread disease such as rat bite fever, marine typhus etc.

3. Unprotected doors and windows

Rodent infestation will be increasing when the bakery doors and windows are unprotected as this aids the rodent to gain free entrance to the bakery thereby making them to thrive well and multiply in numbers.

4. Leftover food

The numbers of rodent will be increasing when there is leftover food in and around the bakery because the leftover food serves as a meal for the rodents, so they will be frequently seen in higher numbers since there is means by which they feed freely. Thus increasing the numbers of rodent and enable them to thrive well.

Signs of rodents’ infestation

1. Droppings: Typically left behind kitchen cabinets, pantries, cupboards, drawers, bins, and anywhere else they think they might find food or where they scurry to avoid predators, rodent are prolific poopers, so it’s pretty easy to spot if you have an infestation. It’s also not uncommon to see droppings along walls on top of wall studs or beams near nest and boxes, bags, old furniture, and other object (Christ 2010).
2. Squeaks and other noise: Rodents aren’t what you’d call quiet. If they’re in your house you’ll hear squeaks, rustling and scampering sounds as they move about and nest. Noises are often more apparent at night as you’re going to bed and they are waking up (Chris, 2010).
3. Urine pools or trails: Rodents are notorious for having weak bladders and they will dribble all over the place. House mice sometimes make things called urinating pillars which are small mounds consisting of grease, dirt and yes, urine. Sometimes you’ll see tiny drops of urine leading to a mound.
4. Sight and sounds: Chris (2010) stated that if you suspect rodent problem, it is probably because you have already seen one in your home. Most rodents are active at night time. He further stated that if you have seen rodent during the day time there is a chances that there is a lot of rodent infestation. During the night time hours the sounds are most likely scratching, gnawing or clawing the walls, cabinets or pantries where baked bread are kept.
5. Burrows: The Norway rat prefers to nest in burrows, whereas the roof rat and house mouse only burrow occasionally. Rat burrows are usually found in earth banks, under concrete slab, alongside building foundation or beneath shrubbery and debris active burrows usually are smooth and compacted at the entrance and free of dust and cobwebs. Fresh rub marks found on hand-parked soil at the opening and the presence of fresh food particles or freshly dug soil at the burrow entrance (scraps) indicate a well established and currently used burrows. Burrows are seldom far from food and water sources. Is determine whether a burrow is active stick a large amount of papers into the opening or cave in the burrow with soil and check it the following day (Olufemi, 2009).

Health implications of rodents’ infestation

Rodent can cause nose nuisance during gnawing, running and mating exercise as a result mans sleep or rest may be disrupted. (Olufemi, 2009). Tobin and Fall (2004, as sited in Alameda 2013) indicated that initial estimate by United Nations (UN) in 1982 revealed that rats alone destroyed ≥ 42 million tons food worldwide that was worth 30 billion dollars. According to Almeida (2013) more importantly rodent play an important role as reservoirs and carries of zoonotic disease for which some epidemic have afflicted mankind for centuries.

WHO (2009) indicate that there are thousand new cases of the plaque that are being registered each year and the figures continue to rise meaning that the plaque remain a threat to mankind. Helen (2010) reported that rodent carry at least 25 diseases. If a rodent is living in your home, you and your family are at risk of contracting some of these diseases as well. Disease is easily and quickly spreads through the disease rodents carry include:

• Plaque
• Rat-bite fever
• Marine typhus
• Rickettsail
• Lephospinosis
• Hantavirus pulmonary syndrome (HPS)
• Pseudorabies
• Salmonellosis
• Swine dysentery
• Toxoplasmosis etc.

Plaque: It is an infections contagious and often fatal disease of rodents and man caused by Yesinia pestis. It is transmitted from rodents to man by the rat fleas. There are three forms of the disease. Bubonic plaque which is characterized by the appearance of buboes on the armpit in the groin or on the neck (bubo is swelling of lymph nodes). Septicemia plaque when the bacteria invade the blood: pneumonic plaque when the lungs are infected (Olufemi, 2009).

Marine typhus: The disease is caused by Rickettsia Typhi and it is transmitted from rats, to man by the rat fleas, Xenopsylla Cheopis. Its symptoms include fever, headaches and muscular pain (Olufemi, 2009).

Rickettsial pox: The disease is caused by Rickettsia Akari it is transmitted from rats to man by rat fleas. Symptom includes high fever, headache, muscle aches, skin rashes and damage to lining of the blood vessels (Olufemi, 2009).

Rat – bite fever: This is primarily the disease of rats transmitted to man through the bite of a rat; it is caused by either Streptobacillosis or Sprillumminus in which case disease is called Spriillosis (Olufemi, 2009).

Economic importance of rodents

The economic importance of rodents according to Olufemi (2009) includes the following:

• As a result of their gnawing and feeding activities, they destroy or reduce aesthetic values of the household materials e.g. woodwork, painting, furniture etc.
• They destroy large quantity of bread/cake resulting in their reduction.
• Damage by rodents also reduces the nutrient values of the food.
• Contamination of food stuff by feaces or urine reduces the marketability or quality of such materials.
• Occasional burrowing by Norway rats underneath baking stores, may lead to structural subsidence particularly of floors and sometimes of road and pavements which may cause accidents.
• They damage wooden doors windows and frames of all kinds in premises where food is stored in their effect to gain access.
• Water pipes may also be damaged due to their gnawing activities causing indoors flooding.
• Burrowing or gnawing on the thermal insulation of the building. Sometimes causes costly damage to electrical wiring causing a fire hazard poor failure and equipment failure.
• They may cause household accidents e.g. collapse of gnawed tables, chairs, shelves etc.
• Rodents contaminate, dirty and foul the environment with their faces, urine and ruminants of food eaten.
• In some communities rodents are a source of protein.

Control of rodents infestation

Prevention is better than cure is just as true for rodents as it is for pests and diseases. Therefore the prime objective of any rodent control campaign is condition which will discourage or prevent the pests from re-entering an area infested. This could be achieved through the following measures:

1. Sanitation

Rodent requires food and shelter. Therefore it is most important to reduce the availability of these any kind of strategy. In building the most affective method of prevention is the improvement of hygiene or sanitation in and around them. Primarily this means sweeping the stores and keeping both it and the surrounding area neat and tidy i.e. free from any object such as empty containers idle equipment or discarded building materials which could provide cover or nesting places for rodents. It also means removing feeding scraps left over from feeding pets or domestic stock.

2. Physical control: This includes the following:

• Hunting: This is the deliberate searching out of rodents and killing those using physical means such as with sticks, cutlasses or batons.
• Flooding: Rodent holes may be flooded with water in orders to kill or scare away rodents.
• Sand filling: Burrows made by rodents may also be filled with sand.
• And use of trap: This is the use of catch alive trap and the brake back trap (Olufemi, 2009).

3. Chemical control: The use of chemicals such as loses warfront etc. incorporated into food as baits to act as coagulants (present blood from clothing (Olufemi,2009).
4. Use of predators (natural enemies): This is the use of animals such as cats as predators against rats.
5. Fumigation: This is the use of chemicals like hydrogen cyanide as a fumigant to destroy or kill rats.

References

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American Centres for Disease Control (2011). Code of Practice for the Prevention and Control of Rodent’s Infestation on Poultry Farm. Retrieved June 15, 2015 from http//:www. dorlandis.com/wsearch. Jap.

Belfast, T. (2009). Bakery tech. Retrieved October 2, 2015, from http//:www.belfast telegraph.co.uk/news.

Chris, W. (2010). Signs of Rodent Infestation. Retrieved may 24, 2015 from http//:www. colonialpest.com/5.

Factmaster (2010). Rodent infestation. Reterived October 2, 2015 from http//:www.factmaster.com

Halimah, M. S. (2015). Improper Dumping of Food Waste 24^th July, 9:05am CBS Local Media a Division of CBS Radio.

Herwig, L. (2006). Plague Overview in Ratzooman Workshop. Retrieved October 2, 2015 from http//:www.Nri.org/ratzooman.

Merriam Webster College (2010). Rodent Infestation and its Health Implication. Retrieved October 2, 2015 from http//:www.merrian webster.com/…./infest.

Olorunda, J. O., Adjase, E. T., Conteh,  A. A., Olanipekun, A. L., Simeon, O., Sadig, J. O. & Harouna, A. (2013). Integrated Question and Answer For Health Students and Professionals in West African. Akure. His Mercy.

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Olufemi, P. (2009). Introduction to Public Health Pest Management. Ibadan: Book Wright.

Orikin, L. (2015). Environmental Health Effects of Rodent Infestation. Retrieved on 24^th May, 2015 from http//:www.pestcontrolflorida.com.

Watchtower Bible Tract Society (2006, May 14). When Rodent Spread Disease. Awake, 165 (89), 6-11.