The Ebola virus causes a hemorrhagic fever, similar to those produced by other producers virus hemorrhagic fevers clinical features. This virus causes severe disease, often fatal, and affects people and nonhuman primates (monkeys, gorillas, chimpanzees). When infection occurs, symptoms begin suddenly and include fever, muscle pain, weakness, headache, and sore throat. Subsequently, patients report vomiting, diarrhea, renal and liver failure, maculopapular rash, and symptoms and signs of internal and external bleeding. In the end, patients develop multiorgan failure. Human transmission occurs through blood or secretions such as urine, feces, semen, breast milk and possibly others as well as exposure to contaminated with infected secretions objects. Patients can transmit while in feverish state, and even postmortem.
The incubation period can be between 2 to 21 days after exposure, but more often is between 8 and 10 days.
Common symptoms are:
Fever, headache, muscle and joint pain, weakness, diarrhea, vomiting, abdominal pain, anorexia.
Other symptoms that some patients are:
Rash (rash), ocular redness, cough, sore throat, chest pain, difficulty breathing, difficulty swallowing, external and internal bleeding.
A significant proportion of infected dies, but some patients recover, not knowing exactly why an evolution or another. It is known that patients who die have not developed a significant antibody response.
Transmission from the natural reservoir people can occur through contact with live or dead infected animals. There have been many studies to know the natural reservoir of infection, investigated many species of mammals, arthropods and plants. In some cases we found nucleic acid sequences, but everything suggests that are the consequence of being infected from another reservoir. Currently, the reservoir admitted fructivoros are several species of bats (hammer-headed bat, Epomops franqueti and Myonycteris torquata). As indicated above, the inter - human transmission of this virus infection occurs through direct contact with blood, secretions, tissues, organs and body fluids of infected live or dead people. The person - to - person transmission is the main mechanism of infection, the risk being higher in the final stage of the disease.
The Ebola virus is a Filoviridae (Gender Ebolavirus) with five subspecies currently supported, phylogenetically distinct:
- Ebola virus - Zaire ebolavirus (EBOV).
- Virus Sudan - Sudan ebolavirus (SUDV).
- -Thai Taï Forest virus Forest Ebolavirus (TAFV) (formerly Côte d'Ivoire ebolavirus).
- Virus Bundibugyo -Bundibugyo ebolavius (BDBV).
- Ebolavirus -Reston Reston Virus (RESTV): non - pathogenic for humans. This subspecies has been isolated from monkeys imported to the US cynomolgous and Italy from the Philippines.
The current outbreak started in March 2014 in Guinea Conakry, the largest outbreak ever known, is caused by a homologous strain of the subspecies "Ebola virus" (Zaire ebolavirus, EBOV). Subsequently, it has spread to other West African countries.
Laboratory diagnostic procedures
Initial symptoms of the disease are nonspecific and may occur in patients with common infections. Therefore virological laboratory diagnosis is required.
There are several options virological diagnosis:
- Detection of viral nucleic acid (RNA) in the sample obtained from the patient: this is the procedure of choice for surgery is performed in quenched samples from the point of view of infectivity. It is also the fastest procedure, and also allows the characterization of the virus to identify its subspecies.
- Culture isolation and identification: this option is not recommended to be slower than the nucleic acid detection, require handling samples without inactivating, involve increased risk to laboratory personnel, and then require the identification of the isolated virus, using identical procedures to which can be applied to patient samples.
- Viral antigen detection: no interest when available methods of detecting nucleic acids.
- Detection of specific IgM or IgG class: usually without interest and to confirm only those probable cases have been able to recover from the disease, or to study possible contacts. Tests in IVAMI:
- RT-PCR tests with various genes of Ebola virus in any of the samples received.
General rules. The following should be considered:
- The virus is found in blood in detectable concentrations about 3 days after the onset of symptoms, mainly after fever, so we do not recommend testing before 3 days of the onset of fever.
- The virus is still present in blood for 3 to 10 days after onset of symptoms, and can sometimes be detected until several months in some secretions.
- Blood whole blood sample anticoagulated with EDTA extracted (1 vial with 5 to 10 mL). No spin, or manipulated outside the laboratory.
- Urine sealed tube containing about 10 mL.
Follow instructions below, regarding the handling and protection of the containers with the samples.
Preservation and shipment of sample:
Keep refrigerated (preferred) for less than 2 days prior to transport to be at room temperature.
Safety measures for handling samples
Follow strict infection control, for contact with the samples or containers containing them , and include:
- While taking samples, the following measures would also continue.
- Any procedure that involves contact with blood, other body fluids, secretions of the patient, or aerosol generation must be performed under strict conditions of protection. To do this, the person performing obtaining the sample, such as blood collection, will be provided with face shield, or alternatively goggles and type FFP2 masks, as well as two pair of gloves, and waterproof gown liquid. Never system traditional needle and syringe, but a vacutainer type puncture protection system will be used. Once the blood sample the material used will be introduced in a system of infectious waste, or if not available it will be introduced in containers with bleach.
- Never any process involving open primary containers where the samples have been obtained, for example aliquoted samples were performed.
- The samples will be sent to the system TRIPLE PACKAGING. This system comprises a primary container protection (sealed plastic bag or container biosafety as provided by Sarstedt, where the tubes are introduced to the samples, absorbent material in ). The primary protection container, is placed in a container secondary protective, sealing and pinch resistant. The secondary protective container will be introduced into an approved shipments of infectious material, cardboard, perfectly identified with the indication of infectious material, and the destination packaging.
- I mportante, as already mentioned, be provided that the containers containing the samples obtained from the patient (for example tube blood collection vacutainer type), should not be opened, and be introduced into a container of primary protection is provided on its an absorbent material inside the acquiring sheet for example. This container should be sealed primary protection.
- Clean any surface, where they have been located or handled samples, with sodium hypochlorite (bleach) diluted 1:10.
- Wear a mask with FFP2 respirator.
- Get double pair of gloves.
- Use waterproof coat.
- Completely cover legs and shoes.
- Wear face shield or goggles as an alternative laboratory.
- Hand hygiene before and after handling the containers with the samples.
Cost of the test: