Sunitha Joseph Central Veterinary Research Laboratory ... · (Habronema muscae). Female flies lay eggs on freshly deposited horse turd and developing fly larvae ingest the parasite

Sunitha Joseph

Central Veterinary Research Laboratory

(CVRL)

Dubai, UAE

STATISTICAL DATA

DIAGNOSTIC CHALLENGES

CVRL’s ROLE IN THE EQUINE INDUSTRY

• African horse sickness (AHS)

• Contagious equine metritis (CEM)

• Dourine

• Equine encephalomyelitis (Western,

Eastern)

• Equine infectious anaemia (EIA)

• Equine influenza (EI)

• Piroplasmosis

• Equine rhinopneumonitis (ERP)

• Equine viral arteritis (EVA)

• Glanders

• Venezuelan equine encephalomyelitis

• Anthrax

• Japanese encephalitis

• Screwworm

• Rabies

• Vesicular stomatitis

• West Nile fever

Equine specific diseases

Multi-species diseases

affecting equines

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

9,917 10,534

11,352

9,419 9,757 10,224

15,993 15,534

10,630 11,219

Others*: Syria, Kuwait, Lebanon, Iran, Hong Kong etc.

42.1%

10.5% 9.3%

14.2%

8.7%

6.0%

3.7% 1.4%

1.4% 1.4%

1.3% Dubai

Sharjah

Abu Dhabi

Qatar

Bahrain

Saudi Arabia

Oman

Mauritius

Egypt

Jordan

Others*

AHS Dourine EIA Glanders EVA

4,256

6,242

7,502

6,652

1,576

CEM EI Piroplasmosis ERP

383 421

156

31

4,942

778

608

532

249

137

82

70

60

22

17

4

1

United Arab Emirates

Qatar

Bahrain

Saudi Arabia

Oman

Egypt

Mauritius

Jordan

Syria

Lebanon

Iran

Hong Kong

Sudan

2,010

825

456

288

167

148

137

125

60

22

17

1

United Arab Emirates

Qatar

Bahrain

Saudi Arabia

Oman

Mauritius

Egypt

Jordan

Syria

Lebanon

Iran

Sudan

4,331

603

574

226

137

115

82

70

60

22

17

2

2

1

United Arab Emirates

Bahrain

Qatar

Saudi Arabia

Egypt

Oman

Mauritius

Jordan

Syria

Lebanon

Iran

Kenya

United Kingdom

Sudan

4,570

651

582

326

137

135

81

70

60

22

17

1

United Arab Emirates

Bahrain

Qatar

Saudi Arabia

Egypt

Oman

Mauritius

Jordan

Syria

Lebanon

Iran

Sudan

828

387

120

81

56

29

28

27

15

4

1

United Arab Emirates

Qatar

Bahrain

Saudi Arabia

Oman

Egypt

Jordan

Syria

Lebanon

Hong Kong

Sudan

291

76

15

1

United Arab Emirates

Qatar

Saudi Arabia

Sudan

CEM

24

6

1

United Arab Emirates

Saudi Arabia

Qatar

ERP

Screwworm West Nile

fever Rabies

Vesicular stomatitis Anthrax

Japanese encephalitis

110

62

12 3

0 0

210 202

18 15 8 6 2 3 3 1 1 1 1 0 0 0 0 0

Cross Reactions

Anticomplementary Species

Sensitivity

Rhodococcus equi infection

This is an important cause of disease and death in foals worldwide and has been diagnosed in increasing numbers also in the UAE parallel to increased equine breeding. Beside classical signs of R. equi pneumonia (Figure 1), extra pulmonary manifestations can occur with intra-abdominal abscessation (Figure 2) and ulcerative enterotyphlocolitis. The pathogen grows well on blood agar (Figure 3).

STRANGLES (Streptococcus equi subsp. equi)

STRANGLES (Streptococcus equi subsp. equi) Strangles outbreaks are on the rise. In the UK alone each year approximately 1000 outbreaks occur. The United Arab Emirates currently experiences an outbreak which involves ponies, miniature horses and adult horses. Diagnosis through culture is no longer regarded as the gold standard. For the identification of Streptococcus equi subsp. equi, a new ‘’triplex’’ qPCR has been evaluated with a sensitivity of 94% and specificity of 97%. At CVRL above mentioned diagnostic methods are used along with an indirect antibody ELISA. This is our preferred tool for testing horse samples for import and export. A horse which is negative in the ELISA and remains free of clinical disease is safe to enter the country. A horse which is serologically positive should be further investigated through qPCR with three consecutive nasopharyngeal washes taken at weekly intervals. If all three PCRs are negative the horse is declared safe to enter the country. Typical beta haemolytic colonies of Streptococcus equi subsp. equi on sheep blood agar, after incubation anaerobically for 24 hrs at 37°C.

The Old World Screwworm, Chrysomya

bezziana, is an obligate parasite of mammals during its larval stage. In hot climates, the whole life cycle can be completed in 3 weeks. The adult female fly deposits every 3-4 days in average 175 eggs in one batch in wounds, but also on wet unbroken skin or on mucous of natural body openings. The 1st instars hatch 12-24 h after egg deposition and the final 3rd stage instar reaches maturity 5-7 days later. Fully fed larvae leave the host to burrow into the ground where the pupation takes place. The pupal stage lasts 8 days at 28 oC. Female flies are ready to mate when they are 3 days old and deposit their first batch of eggs 4 days later. Fig 1: Traumatic myiasis. C. bezziana 3rd instar infestation of a wound of the lower limb of a camel Fig. 2: The striking 3rd instar of C. bezziana is 15 mm in length. There are two mouth hooks at the anterior end and prominent rings of simple pointed thorn like spines around the body. Fig. 3: The mouthparts consist of a pair of mouth hooks and the cephalopharyngeal skeleton. The extensive damage to host tissues is a result of tearing by these mouth hooks. Fig. 4: Posterior spiracular plates visible at the posterior face of the terminal segment have a darkly pigmented, incomplete peritreme partially enclosing three slits pointed towards the break in the peritreme. Fig 5: After maturation, the 3rd instar fall to the ground to become pupa enclosed in a dark brown coloured barrel shaped puparium. Fig 6: The adult screwworm fly is larger than a housefly and has a metallic blue to blue-green coloured body without stripes. It can be distinguished from C. megacephala by the white colour of the lower calyptor (arrow)

House flies and equine stomach worms

The house fly (Musca domestica) is one of the most common insect in livestock farming enterprises. The success of this insect can be explained by a high multiplication rate and the modest lifestyle. Due to high population densities of houseflies and their synanthropic behavior these flies are not only nuisance for animals and humans and mechanical vectors for infectious diseases but also intermediate host for the pale stomach worm of the horse (Habronema muscae). Female flies lay eggs on freshly deposited horse turd and developing fly larvae ingest the parasite eggs. Development of the parasite goes parallel to the development of the fly. After the adult fly emerges from pupal stage it already contains infective Habronema larvae that measure 2-3 mm in length. As much as 25 to 35 larvae had been counted in a single fly. These larvae migrate into the mouthparts of the fly and leave the insect when it is resting on the head of the horse. Since flies are attracted to wounds these nematode larvae can become deposited here and cause the so called ‘summer sores’. Habronema larvae can also migrate into the lungs and cause pulmonal

habronemosis that might be fatal.

Biosafety L-3 Laboratory inaugurated in Dubai A high security laboratory belonging to Central Veterinary Research Laboratory, Dubai was opened on 18th March 2013 by UAE Minister of Environment and Water H. E. Dr. Rashid Bin Fahad. The Biosafety L-3 was planned when the UAE experienced an outbreak of glanders in quarantined equids in 2004. During the 27 years of CVRL existence more than 4000 pathogenic strains have been isolated some of which needed an L-3 facility. These strains are now safely stored in the L-3 laboratory. The highly sophisticated technology was installed by different German companies and its follow-up and logistics was done by Renate Wernery and Dr. Kinne from CVRL.

Parascaris in horses... (not spaghetti)

Due to the hot and dry climate endoparasites in horses are of lesser concern in the UAE. However, under certain circumstances ascarids can become a problem in foals. The picture shows a burden of 256 specimens of Parascaris equorum (weight 800 g) recovered from a worm ileus in a foal. P. equorum has a direct life cycle. The thick shell protects the egg from environmental influences. To prevent clinical outbreaks of parascaridosis regular faecal checkups and anthelminthic treatments are necessary.

A new Rabies incident in UAE

In 1992 the first rabies outbreak was confirmed in the UAE, which affected different animal species including dromedaries. During November 2012 a fox was diagnosed with rabies on a camel farm (see attached picture with rabies particles in the Hippocampus in the immunofluorescence stain, IFT). The sequence analysis of the rabies virus revealed the highest sequence identity (97%) with a rabies virus strain from Oman. This result indicates that foxes in United Arab Emirates maintain rabies virus in their population most probably since the outbreak in Oman and UAE. It is not known if livestock has been affected by this disease.