Infection with Rift Valley fever virus

Article 8.15.1.

General provisions

1. The aim of this chapter is to mitigate the animal and public health risks posed by Rift Valley fever (RVF) and to prevent its international spread.

2. Humans and many animal species are susceptible to infection. For the purposes of the Terrestrial Code, RVF is defined as an infection of ruminants with Rift Valley fever virus (RVFV).

3. The following defines the occurrence of infection with RVFV:

   1. RVFV, excluding vaccine strains, has been isolated and identified as such from a sample from a ruminant; or

   2. antigen or ribonucleic acid specific to RVFV, excluding vaccine strains, has been identified in a sample from a ruminant epidemiologically linked to a confirmed or suspected case of RVF, or giving cause for suspicion of association or contact with RVFV; or

   3. antibodies to RVFV antigens which are not the consequence of vaccination, have been identified in a sample from a ruminant with either epidemiological links to a confirmed or suspected case of RVF, or giving cause for suspicion of association or contact with RVFV.

4. For the purposes of the Terrestrial Code, the infective period for RVF shall be 14 days.

5. In areas where RVFV is present, epizootics of RVF may occur following favourable climatic, environmental conditions and availability of susceptible host and competent vector populations. Epizootics are separated by inter-epizootic periods.

6. For the purposes of this chapter:

   1. 'area' means a part of a country that experiences epizootics and inter-epizootic periods, but which does not correspond to the definition of zone;

   2. 'epizootic of RVF' means the occurrence of outbreaks at an incidence substantially exceeding that during an inter-epizootic period;

   3. 'inter-epizootic period' means the period of variable duration, often long, with intermittent low level of vector activity and low rate of virus transmission, which is often not detected;

   4. ruminants include dromedary camels.

7. The historical distribution of RVF has been parts of the African continent, Madagascar, some other Indian Ocean Islands and the south western Arabian Peninsula. However, vectors, environmental and climatic factors, land-use dynamics, and animal movements may modify the temporal and spatial distribution of the infection.

8. When authorising import or transit of the commodities covered in the chapter, with the exception of those listed in Article 8.15.2., Veterinary Authorities should require the conditions prescribed in this chapter relevant to the RVF status of the ruminant population of the exporting country.

9. Standards for diagnostic tests and vaccines are described in the Terrestrial Manual.

Article 8.15.2.

Safe commodities

When authorising import or transit of the following commodities and any products made from them, Veterinary Authorities should not require any RVF-related conditions, regardless of the RVF status of the ruminant population of the exporting country:

1. hides and skins;

2. wool and fibre.

Article 8.15.3.

Country or zone free from RVF

A country or a zone may be considered free from RVF when infection with RVFV is notifiable in the entire country and either:

1. it meets the requirements for historical freedom in point 1 a) of Article 1.4.6.; or

2. met the following conditions:

   1. an on-going pathogen-specific surveillance programme in accordance with Chapter 1.4. has demonstrated no evidence of infection with RVFV in ruminants in the country or zone for a minimum of ten years; and

   2. during that period no indigenous human cases have occurred in the country or zone.

A country or zone free from RVF will not lose its free status through the importation of ruminants that are seropositive, so long as they are either permanently identified as such or destined for immediate slaughter.

Article 8.15.4.

Country or zone infected with RVFV during the inter-epizootic period

A country or zone infected with RVFV, during the inter-epizootic period, is one in which virus activity is present at a low level but the factors predisposing to an epizootic are absent.

Article 8.15.5.

Country or zone infected with RVFV during an epizootic

A country or zone infected with RVFV, during an epizootic, is one in which outbreaks of RVF are occurring at an incidence substantially exceeding that of the inter-epizootic period.

Article 8.15.6.

Strategies to protect from vector attacks during transport

Strategies to protect animals from vector attacks during transport should take into account the local ecology of the vectors and potential risk management measures include:

1. treating animals with insect repellents prior to and during transportation;

2. loading, transporting and unloading animals at times of low vector activity;

3. ensuring vehicles do not stop en route during dawn or dusk, or overnight, unless the animals are held behind insect-proof netting;

4. using historical and current information to identify low risk ports and transport routes.

Article 8.15.7.

Recommendations for importation from countries or zones free from RVF

For ruminants

Veterinary Authorities should require the presentation of an international veterinary certificate attesting that the animals:

1. were kept in a country or zone free from RVF since birth or for at least 14 days prior to shipment;

AND

2. either:

   1. were vaccinated at least 14 days prior to leaving the free country or zone; or

   2. did not transit through an area experiencing an epizootic during transportation to the place of shipment; or

   3. were protected from vector attacks when transiting through an area experiencing an epizootic.

Article 8.15.8.

Recommendations for importation from countries or zones infected with RVFV during the inter-epizootic period

For ruminants

Veterinary Authorities should require the presentation of an international veterinary certificate attesting that the animals:

1. showed no sign of RVF on the day of shipment;

2. met one of the following conditions:

   1. were vaccinated against RVF at least 14 days prior to shipment with a modified live virus vaccine; or

   2. were held for at least 14 days prior to shipment in a vector-protected quarantine station, which is located in an area of demonstrated low vector activity. During this period the animals showed no clinical sign of RVF;

AND

3. either:

   1. did not transit through an area experiencing an epizootic during transportation to the place of shipment; or

   2. were protected from vector attacks when transiting through an area experiencing an epizootic.

Article 8.15.9.

Recommendations for importation from countries or zones infected with RVFV during an epizootic

For ruminants

Veterinary Authorities should require the presentation of an international veterinary certificate attesting that the animals:

1. showed no sign of RVF on the day of shipment;

2. did not originate in the area of the epizootic;

3. were vaccinated against RVF at least 14 days prior to shipment;

4. were held for at least 14 days prior to shipment in a vector-protected quarantine station, which is located in an area of demonstrated low vector activity outside the area of the epizootic. During this period the animals showed no sign of RVF;

5. either:

   1. did not transit through an area experiencing an epizootic during transportation to the place of shipment; or

   2. were protected from vector attacks when transiting through an area experiencing an epizootic.

Article 8.15.10.

Recommendations for importation from countries or zones not free from RVF

For semen and in vivo derived embryos of ruminants

Veterinary Authorities should require the presentation of an international veterinary certificate attesting that the donor animals:

1. showed no sign of RVF within the period from 14 days prior to and 14 days following collection of the semen or embryos;

AND

2. either:

   1. were vaccinated against RVF at least 14 days prior to collection; or

   2. were demonstrated to be seropositive on the day of collection; or

   3. testing of paired samples has demonstrated that seroconversion did not occur between semen or embryo collection and 14 days after.

Article 8.15.11.

Recommendations for importation of fresh meat and meat products from ruminants from countries or zones not free from RVF

Veterinary Authorities should require the presentation of an international veterinary certificate attesting that the entire consignment of meat comes from:

1. ruminants which showed no clinical sign of RVF within 24 hours before slaughter;

2. ruminants which were slaughtered in an approved slaughterhouse/abattoir and were subjected to ante- and post-mortem inspections with favourable results;

3. carcasses which were submitted to maturation at a temperature above 2°C for a minimum period of 24 hours following slaughter.

Article 8.15.12.

Recommendations for importation from countries or zones not free from RVF

For milk and milk products

Veterinary Authorities of importing countries should require the presentation of an international veterinary certificate attesting that the consignment:

1. was subjected to pasteurisation; or

2. was subjected to a combination of control measures with equivalent performance as described in the Codex Alimentarius Code of Hygienic Practice for Milk and Milk Products.

Article 8.15.13.

Surveillance

Surveillance should be carried out in accordance with Chapter 1.4.

1. During an epizootic, surveillance should be conducted to define the extent of the affected area.

2. During the inter-epizootic period, surveillance and monitoring of climatic factors predisposing an epizootic should be carried out in countries or zones infected with RVFV.

3. Countries or zones adjacent to a country or zone in which epizootics have been reported should determine their RVF status through an on-going surveillance programme.

To determine areas of low vector activity (see Articles 8.15.8. and 8.15.9.) surveillance for arthropod vectors should be carried out in accordance with Chapter 1.5.

Examination of vectors for the presence of RVFV is an insensitive surveillance method and is therefore not recommended.

nb: first adopted in 1986; most recent update adopted in 2016.