A mysterious disease killing cattle

It seems that whenever one wants to attract attention in Ghana, the phrase has to be “a mysterious or strange disease”. Just yesterday 24th February, early in the morning, I received news by Whatsapp from an alarmed language student of mine about a supposedly new disease – “a mysterious or strange disease” from China. Even before BBC came out in its evening news with information to dispel the rumour, I had already done a quick write-up and spent the whole day and next morning sending it around. Simply put, the subject of the rumour – the hantavirus – is not communicable and transmissible like our current coronavirus or cholera. Simply put, again, the hantavirus is not dangerous!

The following, however, is about another disease we have faced with cattle in Ghana recently, and about which the air needs to be cleared as quickly as possible. In addition, it is of essence that measures be taken to tackle this “mysterious, strange disease”, before it spreads and becomes an economic threat to our agriculture and nation.

In early January this year, there were reports in the media (newspapers, tv, Internet websites etc.) of a strange disease that hit herds of cattle at Dedenu, a suburb of Yorkitikpo and its environs in the South Tongu district of the Volta Region. This was especially reported by the Ghanaian Times on 10th January 2020, and subsequently by their reporter Lawrence Vomafa. The disease was said to be called ‘suffer’ by the cattle owners – ostensibly due to the enormous pain it inflicts on the animals, and it had reportedly killed over 30 cows within 10 days.

The reports stated that the disease begins with swollen and bleeding hooves and later metamorphoses into dark spots on the animals, leading to swelling of the joints and tongue; thus making the animals unable to feed and/or drink water, resulting in rapid weight-loss. The animals, after a few days, reportedly started dripping saliva from the mouth and nostrils and were unable to move long distances. According to the report, when a Ghanaian Times reporters visited the area in early January some of the dead animals were still in the bush, while those too weak to move or feed had visible signs of the disease as they had become very lean. The seriously affected ones could be seen limping with their bleeding hooves, and slime dripping from their mouths.

The community reportedly had more than 30 kraals with over 3,000 cattle feeding within the same area and drinking from one water source. Fifteen of the cattle owners reportedly told the Ghanaian Times that the disease has caused so much pain for the past seven years, as it affects the animals twice or thrice a year. According to them, they spend between three to four thousand Ghana cedis quarterly in treating the animals, to no avail.

They indicated that veterinary officers who took blood samples of the animals two years ago are yet to tell them the disease’s exact cause and how it can be eradicated. Reportedly, the cattle owners who have been battling the disease over the past years seemed to have lost hope when they told the Ghanaian Times the results of laboratory analyses of samples from the cattle taken two years ago have not been made public, while they spend huge sums of money to vaccinate and treat the animals each year.

One Mr. William Adeti, who owns about 200 cattle, said they regularly vaccinate the animals yet the disease keeps recurring; as such, they do not know what to do now. Laboratory results from the actual disease that struck hundreds of cows at Dedenu in the South Tongu District in the Volta Region were to be released in January, but as of now there has been no public announcement of the results.

The District Veterinary Services Director, Dr. Jehadi Osei-Bonsu, said the preliminary investigations have begun; and even though foot and mouth disease (hoof and mouth disease) is suspected, the yet-to-be released results will disclose the actual disease. This followed a visit by a team of veterinary experts to the area who took samples of the affected animals, including the carcasses, and studied the environment as well as the source of feeding and drinking water.

The veterinary team’s visit was the result of a Ghana Times report in early January 2020, about a strange disease that had hit herds of cattle at Dedenu and its environs. Dr. Osei-Bonsu said the disease, which he suspects to be foot and mouth disease (hoof and mouth disease) does not kill per se, but the animals die because they cannot feed. He reportedly also said there is no animal disease called ‘suffer’ – adding that the name was coined from a medication called suffer that is used to treat animal foot-disease.

So, in the absence of any public announcement and while awaiting release of results from the tests conducted by Veterinary Services, the following is a write-up on the most probable causal disease – which is Hoof and mouth disease (HMD). However, the results may indicate another disease; so, this write-up is not to preempt the results or to mislead the public, but rather to inform and educate.

 

Hoof and mouth disease (HMD) as it is termed in animals (not to be confused with the Hand, Foot and mouth disease (FMD) in humans) is an infectious and sometimes fatal viral disease that affects cloven-hooved animals, including domestic and wild bovids and also, rarely, humans. Susceptible animals include cattle, sheep, goats, pigs, water-buffalo, antelope, deer, bison and even elephants. It is however commonly called Foot and Mouth disease even by vets, even though the group of animals it infects have no feet but rather hooves.

 

The pathogen

It is a highly contagious viral disease caused by a picornavirus – i.e. it is a single-stranded RNA virus belonging to the genus Aphthovirus of the Picornaviridae virus family. Unfortunately, it has no treatment. We treat the secondary bacterial infections of the animals afflicted with sulfadimidine – hence the name sulfer or suffer given to the disease by farmers in Ghana. At least, in my secondary days I used to apply sulfadimidine to the sore corners of my goats’ mouths, their hoofs and their sore, crusty, head-crowns when they contracted such a disease.

 

Transmission

Researchers believe that with the hoof and mouth disease virus, it is possible that – at least theoretically – a single virion of this pathogen can trigger an infection. The foot and mouth disease caused by an infection with the virus usually occurs locally, and the virus is transmitted primarily through contact and smear-infection when in direct contact with infected animals, or with contaminated pens or livestock vehicles. However, the virus can also be spread through the air. The virus can be found in the clothing and skin of farmers and other people handling animals; in stagnant water, uncooked feed-waste, feed additives containing infected animal products, and animal products such as cheese or meat. Cows can even get HMD from infected bulls through semen transmission. Control measures include quarantine, the destruction of infected herds of cattle, and an export-ban on animal products to countries that are not affected by the disease.

 

People cannot get infected with animal foot and mouth disease. There is no danger for consumers of beef and pork, pasteurised milk or products made from it, even in the event of an epidemic. However, since the disease spreads extremely quickly among animals, HMD is a serious threat to agriculture in any country, including Ghana.

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Occurrence
HMD is spread almost worldwide. It is only in New Zealand that no HMD outbreaks have been registered, while for Australia the last one was in 1872. In the United States the last occurrence was in 1929, and Canada (since 1952), Mexico (since) 1954 and Chile (since 1988) are also HMD-free. HMD is still widespread in Africa, Asia and parts of South America. These regions are considered enzootic – i.e., it regularly affects animals in a particular district or at a particular season, as in Dedenu and its environs; for the past seven years it has reportedly affected the animals twice or thrice in a year.

 

Pathogenesis
At the centre of the infection is a strongly pronounced viremia phase (very rapid multiplication of the virus) in the target organs. The HMD virus has a high affinity for skin and cutaneous mucous membranes (epitheliotropism). Affected are the mucous membranes of the mouth, esophagus and rumen pillars, as well as the hairless skin of nostrils, snout, proboscis, udders and hoofs. The pathogen also affects skeletal and cardiac muscles (myotropism). Neurotropic properties (nerval infection) are rarely observed.

 

Clinical symptoms and course of the disease

Cattle, goats and sheep become infected primarily aerogenically, while pigs are usually infected orally. The blisters called aphtha (‘primary aphtae’) that arise at the point of entrance of the virus usually go unnoticed. The incubation period of HMD is two to seven days in cattle, and one to three days in pigs. The incubation period of the so-called ‘benign hoof disease’ in sheep and goats is 2–14 days.

The signs of the disease are less noticeable in pigs, sheep and goats than in cattle. This incubation period runs with a fever of one to three days up to 42 degrees Celsius. In this case, in cattle there is a sudden drop in milk yield until the milk runs dry. Also, a strong production of viscous saliva (‘HMD beard’) begins at the same time as the fever, with simultaneous reddening of the mouth mucosa. Anorexia, interference of rumination and the occurrence of ‘saliva pools’ near the animals characterise progression of the disease. These were all present in the cases in Dedenu.

 

A visible sign of the virus’ manifestation in other organs is the formation of ‘secondary aphtae’. Predisposing factors such as extreme mechanical stress favour their occurrence. In this further course of the disease, the liquid-filled blisters (aphthae) appear mostly on the roof of the mouth, in the entire mucosa of the mouth and in the tongue area. Subsequently, further aphthae are developed in the hoof area, on the udder skin and on the teats.

The general condition of the animal is highly disturbed. The animals show expressions of pain in the form of closed mouths, smacking jaw movements and lameness. After the bubbles have burst, erosion sores form – some of them large – and the healing process begins. In the process, other animals in the stock constantly fall ill.

 

The healing of lesions in the mouth area takes up to 14 days. The hoof-aphthes heal within a month. The convalescence phase is often disturbed by bacterial secondary infections. In addition to benign disease variants with sometimes mild symptoms (mortality 2–5%), there is also a malignant course of the disease (mortality up to 80%). The cause is highly virulent pathogens with pronounced myotropism. This form is found mostly in calves. Even with mild forms, myocarditis focuses on heart-muscle damage in this age group. Affected animals die within 24 hours with the symptoms of a serious general illness.

 

The natural infection imparts a solid immunity against the respective type of virus for up to 12 months. Dreaded and expected secondary and later damage after surviving infection are secondary bacterial infections, changes in mastitis, possible sole horn and hoof horn detachment, muscle damage, myocarditis as well as persistent massive performance depressions and loss of condition.

 

In pigs, the hoofs are primarily affected by the formation of aphthae, which is manifested predominantly at the crown margin and in the interhoof gap. The changes on the proboscis disk and oral mucosa are rather unremarkable. The sow also has suckling sores.

 

The clinical picture of the older pigs is characterised by (support leg) lameness/limping of various degrees of severity up to the point of being immobile. At first only a few animals are affected, but the disease spreads within a few days in the herd. Suckling piglets and runners suffer sudden deaths from heart-muscle damage. The epithelial lesions on the trunk and breasts heal within two weeks; and with crown hem and sole defects, the course of the disease is usually made difficult by purulent secondary infections.

 

Immunity in pigs after infection lasts for five to seven months. In addition to mastitis, metritis and abortion, later and consequential damage means that the animals are worn-out and myocarditis-related performance losses arise.

 

In cattle, the most important differential diagnoses (diseases with similar symptoms) include vesicular stomatitis, mucosal disease, bovine plague, malignant catarrh fever, infectious bovine rhinotracheitis and smallpox. In swine, diseases with similar symptoms include other swine diseases of the vesicular disease complex, all of which are associated with vesicle formation: vesicular stomatitis (VS), swine vesicular disease (SVD) and vesicular exanthema (VES). In addition, selenium poisoning can be used for differential diagnosis in swine.

 

As a student in agriculture up to the 6th form and thereafter, I reared goats in Cantonments and near Sankara/Ako Adjei Circle and I encountered the Hoof-and Mouth disease in my herds a number of times. The literature says that in sheep and goat the incubation period of the so-called ‘benign hoof disease’ is 2–14 days. The signs of the disease are less noticeable in sheep and goats than in cattle.

The focus in sheep is on the formation of aphthae on the crown margin and in the interhoof gap. Changes to the mouth and lips are often uncharacteristic. The herd is infected slowly and incompletely (within three to six weeks). The only signs of the disease are often painful and severe lameness. From the third day of lameness, the reddened sores become clearly visible after the aphthae have burst. The mortality of adult animals is low. In lambs, the malignant myocarditic form with fever, diarrhea and apathy dominates. The losses are up to 80% and the animals die with no signs of aphtha. The lesions heal within two to three weeks, although secondary infections complicate the course.

In goats, the disease is either mild or severe, combined with myocardial damage and high lethality. There is a febrile phase with general disorders and milk decline. The formation of aphthae in the mucous membrane of the mouth is clear; but due to them bursting soon, the presence of the blisters is short-lived. In the head area there can be sore, crusty swellings when the hair – mostly between the horns – is raised (so-called thick head); something I remember quite clearly appearing in my goats then. Rhinitis is often present. Hoof aphthae are rarely observed.

Late and consequential damage in small ruminants like goats and sheep are hoof infections, abortions, metritis and mastitis. The type-specific immunity after field virus infection lasts one to two years and longer.

 

Similar changes as the HMD are caused by the rotting limp or sheep panitomy (caused by the bacterium Dichelobacter nodosus, secondary is often also Fusobacterium necrophorum), lip grind (Ecthyma contagiosum), and the sheep and goat pox in sheep and goats.

 

In humans, due to their low susceptibility, people are affected extremely rarely by the disease and there is a favourable prognosis for the disease. Infection occurs directly through contact with infected animals or as a result of laboratory infection. Indirect transmission via infected milk is also possible. In humans, in terms of differential diagnosis, the viral-related disease commonly known as hand-foot-mouth rash that is associated with very similar symptoms must be differentiated. It is more commonly described in humans, especially young children. This disease is caused by another virus from the Picornaviridae family, the enterovirus Coxsackie A.

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Diagnosis
In clinical terms, the clinical picture is usually clearly pronounced. The diagnosis of small ruminants is often complicated by inapparent and mild forms. The occurrence of sudden lameness in a large part of the herd with simultaneous increased peracute mortality in newborn and/or very young lambs gives first indications of hoof-and-mouth disease even before pathognomonic evidence of aphthae formation. In pig herds, differential diagnosis of hoof and mouth disease must be considered as soon as frequent leg lameness in connection with blisters occurs in predisposed areas for the formation of aphthae.

 

If, therefore, there is suspicion of hoof-and-mouth disease, actual outbreak of the disease must be officially determined – i.e. by veterinarians, laboratory tests and based on law. According to Art 1 of the German ‘Ordinance for Protection against Hoof and Mouth Disease’ (MKS-VO), an outbreak of the disease is only considered proven if the pathogen detection is in the form of virus antigen or viral RNA. This also applies even in the event of clinical symptoms being absent. In addition, the serological detection of antibodies against HMD or an increase in titer in demonstrably non-vaccinated animals is binding. What pertains in Ghana is as yet unclear.

 

On-site measures

A thorough check of the animal herd under suitable conditions (good lighting, good cleaning of contaminated predilection sites) in the event of suspicion; a precise knowledge of the clinical picture; and an adequately-sensitised veterinary community are prerequisites for quick detection of the disease.

 

For the detection of infectious virus, antigen or nucleic acid, lymph and cover material from fresh aphthae are best-suited. In the absence of aphthae, swabs can alternatively be removed from the region of transition to healthy tissue. In addition, nasal swabs and organ samples (e.g. modified areas of rumen pillars, heart and udder) can be used as sample material. As stated before, in the EU absolutely no treatment is supposed to be done by the vets or farmers.

 

Control measures

In the EU, until 31st December 1991, mandatory vaccinations of cattle were carried out in to prevent an HMD epidemic. Vaccinations lead to serious barriers for trade: vaccinated people, like infected animals, have antibodies in their blood and can only be distinguished from one another if the vaccines are specially labelled. There is also a risk of spreading pathogens via vaccinated animals. Therefore, vaccinations were prevented by the EU. Therapy measures are also generally not permitted in Europe.

 

I remember vividly the following measures from lectures in veterinary epidemiology and virology at university: If a hoof-and-mouth disease is suspected, the farm concerned is blocked, sick animals are usually culled as a precautionary measure, and samples are examined for hoof-and-mouth disease. Furthermore, a restricted/quarantine area of ​​at least three kilometres is set up all animal populations are examined for HMD; and animal transport is prohibited.

 

If the suspicion is confirmed, the stock of animals is culled and disposed of – as are the neighboring stocks within a radius of one kilometre. No animals or sperm may be transported in the three-kilometre restricted area for 15 days; the roads are blocked. After the 15 days, transports of animals are only permitted with a permit (the animals may only be transported for slaughter).

Milk may only be used for separate processing but not used in the general processing. An observation area will be established within a 10 km radius of the outbreak. Within this area, animals can be transported with permission. If no further diseases have occurred within 30 days after the epidemic, rats and mice are combatted, and cleaning and disinfection are carried out.

Since the virus is very resistant, it can persist for months in the soil, barn, stalls waste and straw. If there is an infestation, extensive disinfection with formic acid or heat (at least 60° C) must be carried out. Measures such as a ban on animal transport are often taken when an HMD epidemic occurs in neighbouring countries. Due to the high resilience, even the wheels of cars are disinfected when crossing the quarantine border during larger epidemics.

Take note that control measures include quarantine, the destruction of infected herds of cattle, and an export ban on animal products to countries that are not affected by the disease. In the case of Ghana, it is very difficult to see how the quarantine measures outlined above, as well as the destruction of infected herds, would be done. However, this and widescale systematic as well as sustained vaccination are the routes to go (even though vaccination is not allowed in the EU, we should allow it even if there is a risk of spreading pathogens via vaccinated animals) if the disease is to be successfully eradicated, as it has been in the EU and elsewhere.

This, however, implies a great commitment has to be made by government in our budgets to combat it, in financial and material terms. In addition, it will mean resourcing the veterinary service and making it take its rightful place in the scheme of things, as the sole authority on inspecting and testing products of animal origin (meat and fish), and to work hand in hand in this respect with the Food and Drugs Board, where Veterinary officials must/should be employed and working.

The recent Salmonella-infested gizzard saga at Tema Port showed clearly the confusion that reigns between governmental departments, agencies and authorities in such matters. It is therefore gratifying to hear from Dr. Stephen George Bonnah, Head of Regulatory Unit, Veterinary Services Directorate at the Port of Tema, that going forward there should be coordination among stakeholder agencies on the Joint Inspection Management Information System that gives approval for the clearance of goods at the port.

“The most important thing is that we should be able to sit down, collaborate and do the right thing, and not assign blame to each other; there should be a mutual understanding between the institutions.” This should pertain at all entry points to the country.

Now, after we have achieved a total eradication of this now-no-more “mysterious, strange disease”, what will be left is maintaining the status quo achieved by preventing any re-importation through our borders – for example, through nomadic herds-people and their cattle. This would entail effectively enforcing our veterinary measures at the places of entry into the country, putting in-coming cattle into quarantine near the borders in the newly conceived and yet-to-be-established grazing paddocks there; and even there, at the quarantine locations, doing randomised yet systematic tests of the herds. The future will then look bright, whereby we will not hear of any “mysterious, strange disease” any more.

 

Sources:

https://www.ghanaiantimes.com.gh/health-alert-strange-disease-kills-cattle-at-dedenu-30-cows-die-in-10-days/

http://ghheadlines.com/agency/ghanaian-times/20200113/133620927/lab-results-on-strange-disease-at-dedenu-to-be-ready-on-wednesday

https://de.wikipedia.org/wiki/Maul-_und_Klauenseuche translated and summarised by the author, Kwadzo Oppong Ameko, an expert translator/interpreter in various languages who trained in veterinary medicine at the University of Leipzig and worked in Ghana for a short while in that field. He is the CEO of Languages Translation and Interpretation Agency Limited based in Adabraka Official Town, with almost three decades of experience in translation of various languages.

For more, see https://en.wikipedia.org/wiki/Foot-and-mouth_disease.

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