Neutralizing based seroprevalence study of Toscana virus in livestock from Algeria

Toscana virus is a sandfly-borne human pathogen belonging to Phlebovirus genus into Phenuiviridae family. It is emerging in north Africa posing a complex threat to public health. TOSV is heavily affecting sandfly-exposed people in northern Algeria. A larger distribution has recently been stated in Algeria by using dog sera. Dog exposure to TOSV was repeatedly identified in north Algeria, with 4.56% lately detected to possess respective neutralizing antibodies. However, evidence for TOSV has only been observed in dogs among various species of domestic animals. Therefore, we attempted to assess sera from 221 livestock comprising cattle, sheep, goats, rabbits and horses, to identify the presence of TOSV neutralizing antibodies. The study was conducted during 2017, in 11 areas from the governorates of Blida, Medea, Algiers, Tipaza, Ain Defla, Tissemsilt in the north center, and Setif, Mila, Tizi Ouzou, Jijel in the northeast of Algeria. Positive results were obtained in 14.6% (12/82) cattle, 17.18% (11/64) sheep, 15% (3/20) horses and 3.33% (1/30) goats, whereas rabbits remained negative. Positive samples originated mainly from the north centre, with new areas being first-ever detected. The seroprevalence was noticed to be very strongly related to sample origin (p < 0.01). Females (OR=4.09) were observed to be more likely infected. Our findings represent a further proof of TOSV circulation in Algeria. Moreover, they revealed a potential role of livestock (p = 0.00731) in its natural cycle. This fact emphasize how important is to elucidate the exact contribution of livestock to the epidemiology of sandfly-borne phleboviruses, and their impact on public health.

Serological evidence of Rift Valley fever viral infection among camels imported into Southern Algeria

Rift Valley fever (RVF) is a mosquito-borne viral zoonosis caused by the Rift Valley fever virus (RVFV). The present work aims to investigate the epidemiological status and identify the risk factors associated with RVFV infection in dromedary camels (Camelus dromedarius) from southern Algeria. A total of 269 sera of apparently healthy camels was collected and tested using a competitive Enzyme-Linked Immunosorbent Assay (ELISA). Overall, 72 camels (26.7 %, 95 % CI: 21.4-32) were seropositive to RVFV. IgG antibodies were found to be most prevalent in camels from south-western areas, particularly in Tindouf wilaya (52.38 %, p < 0.0001), and in camels introduced from bordering Sahelian countries (35.8 %) (OR = 8.75, 95 %CI: 2.14-35.81). No anti-RVFV antibodies were detected in sera collected from local camels (0 %). Adult (5-10 years) and aged (>10 years) camels have a significantly higher risk of being infected by RVFV (OR = 2.15; 95 %CI = 1.21-3.81, OR = 2.05; 95 %CI = 1.03-4.11, respectively). This report indicated that dromedaries imported to the south-western areas are exposed to RVFV and may contribute to its spread in Algerian territories.

Identification of blood source preferences and Leishmania infection in sand flies (Diptera: Psychodidae) in north-eastern Algeria

Leishmaniases are among the most neglected vector-borne diseases, infecting humans as well various animal hosts with clinical outcomes varying from cutaneous disorders to visceral and life-threatening disease. In Algeria, canine leishmaniasis (CanL) caused by Leishmania infantum is endemic mainly throughout the northern regions of the country with the Mediterranean climate that favours the occurrence of Larroussius sand flies, the vectors of the parasite. This study conducted in Bougaa and Kherrata, two regions located in north-eastern Algeria and endemic for CanL, focuses on: i) composition of sand fly fauna, ii) screening of Leishmania parasites and iii) the blood sources of engorged females. Entomological surveys were conducted between June and September 2019 using CDC light-traps in rural areas of both regions. Sand fly specimens were morphologically identified, females were screened for Leishmania DNA using kDNA and ITS1 primers, blood meals in engorged females were identified by peptide mass mapping (PMM)-based MALDI-TOF mass spectrometry and confirmed by DNA sequencing analysis. Overall, 1940 specimens (844 males, 1096 females) were collected, all belonging to the subgenus Larroussius: Phlebotomus perniciosus, (94.64%), Ph. perfiliewi (4.74%) and Ph. longicuspis (0.62%). No Leishmania DNA was detected in the evaluated pools (n = 106) (1096 females). PMM-based MALDI-TOF MS successfully identified a source of blood in 92% (141/154) of engorged females (135 Ph. perniciosus and 6 Ph. perfiliewi). All blood meals were taken from domestic cattle (Bos taurus) except for one originating from a dog (Canis lupus familiaris) and one from sheep (Ovis aries). Sequencing of host cytochrome B gene confirmed these identifications but showed lower success rate of 58% (29/50), demonstrating the high effectivity of peptide mass mapping (PMM)-based MALDI-TOF mass spectrometry for routine identification of blood meals of varying degree of digestion. Our findings represent first record of cattle and dog blood in sand flies in Algeria and striking feeding preference of local sand fly population at domestic sites of studied regions for cattle which may play an important role in parasite transmission. Further studies are needed to better understand potential contribution of cattle to ecology of sand flies and epidemiology of leishmaniasis in north-eastern Algeria.