Retrospective pathological

survey of pulmonary disease in

free-ranging river dolphins

in BrazilThaís Carneiro Santos Rodrigues, José Luis Catão-Dias, Josué Díaz-Delgado, Júlia Luz

Carvalho, Miriam Marmontel

INTRODUCTION

Largest species of river dolphin Adult male can reach 2,55 m and 200 kg

Dark-grey to pink

Dorsal fin long but low in height

Unfused cervical vertebraeInia geoffrensis

INTRODUCTION

Sotalia fluviatilis

Smallest delphinid 1,5 m max length and weight up to 50 kg The only exclusively freshwater delphinid

Dorsal fin falcate, tall but short in length

Light to dark grey Ventral region lighter or pinkish

Fused cervical vertebrae

INTRODUCTION

Endemic of the Amazon and Orinoco basins Brazil, Colombia, Ecuador, Peru, Bolivia and Venezuela

Endemic of the Amazon basin Brazil, Colombia, Ecuador and Peru

INTRODUCTION

Indicators of Amazon’s aquatic ecosystem quality

Keep fish populations healthy and balanced

INTRODUCTION

Limited knowledge?

2011

2012

INTRODUCTION

(2014) Ameaçada

INTRODUCTION

Major known threats

Incidental mortality in fishing netsPopulation fragmentation, isolation, habitat loss *damsEnvironmental pollution *mercury

Inia – Deliberate killing for use as fish bait for catfish(Calophysus macropterus) and to avoid (perceived) fishing competition

INTRODUCTION AND OBJECTIVE

Underlying pre-existing diseases may contribute towards death

Pneumonia and other respiratory diseases have been recognized as important causes of death in both captive and free-ranging cetaceans

Survey on worldwide captive I. geoffrensis: pneumonia as the most common finding (Bonar et al., 2007)

Limited information on free-ranging I. geoffrensis and S. fluviatilis

Pathological survey of pulmonary disease in free-ranging Amazon river dolphin and tucuxi

MATERIALS AND METHODS

Amazonas state

MATERIALS AND METHODS

Dry season Wet season

MATERIALS AND METHODS

MSDR and ASDR Riverside communities

MATERIALS AND METHODS

Carcass collection

1995 – 2016

Necropsy

MATERIALS AND METHODS

10% buffered formalin

Histopatological process

H&E

Gram stain

Parasitological identification (Delyamure, 1955)

RESULTS AND DISCUSSION

24 28

52

25 adults

22♂22♀

16 juveniles 6 neonates

10 ♀ 10 ♂ 10 ♀ 13 ♂

RESULTS AND DISCUSSION

84,6% (44/52) lung samples

Most common respiratory disease PNEUMONIA 53,8%

Verminous pneumonia 25% (13/52)

Bacterial pneumonia 25% (13/52)

Meconium aspiration syndrome 1,9% (1/52)

RESULTS AND DISCUSSION

Verminous Pneumonia

25% Inia geoffrensis 25% Sotalia fluviatilis

Principalmente adultos e jovens de ambos os sexos e um neonato

Multifocal, poorly

demarcated, pale

pink/yellow to dark grey,

firm foci within the pulmonary

parenchyma

2cm

RESULTS AND DISCUSSION

Verminous Pneumonia

Eosinophilic and suppurative to

pyogranulomatous inflammatory

exudate

500µm

Granulomas and fibrosis

Intra-alveolar, bronchiolar orbronchial adult

nematodes

RESULTS AND DISCUSSION

Verminous pneumonia

Halocercus brasiliensis

84,6% (11/13)

Case 35

Sotalia fluviatilis Female Adult Tachypnea Unable to dive

200µm

RESULTS AND DISCUSSION

Verminous pneumonia

Halocercus brasiliensis Pseudaliidae

Nematoda

Halocercus spp.

Most common lungworms in odontocete species

worldwide

Woodard et al., 1969; Dailey, 2001; Measure, 2001

FILO

FAMILY

GENUS

Guiana dolphin Sotalia guianensis

RESULTS AND DISCUSSION

Verminous Pneumonia

Halocercus brasiliensis

Striped dolphins Stenella coeruleoalba

Rosas et al., 2002; Marigo et al., 2010

88% S. guianensisfrom southern and

southeastern coasts of Brazil

40% of cases: probable cause of

death

RESULTS AND DISCUSSION

Verminous Pneumonia

Halocercus brasiliensis

Vertical transmission Conlogue et al., 1985; Dailey et al.,

1991; Moser e Rhinehart, 1993

Female neonate Sotalia fluviatilis

Supports transplacental infestation

RESULTS AND DISCUSSION

Bacterial pneumonia

Suppurative bronchopneumonia

• Bronchiectasis, abundant gram-positive and gram-negative coccoid and bacillary bacteria

• Suppurative inflammatory exsudate

• Fibrosis, tissue remodeling

10cm

RESULTS AND DISCUSSION

Bacterial pneumonia

Case 20

Inia geoffrensisMale Adult Thorax penetrating wound Pyothorax Severe fibrinosuppurative pleuritis of the right lung

5cm

RESULTS AND DISCUSSION

Bacterial pneumonia Case 20

Inia geoffrensisMale Adult Thorax penetratingwound Pyothorax Severefibrinosuppurativepleuritis of the rightlung Severe, diffuse, chronicfribinosuppurativepleuropneumoniaGram+ coccus

500µm 20µm

RESULTS AND DISCUSSION

Bacterial pneumonia

Several species of bacteria isolated from cetacean lungsParsons e Jefferson, 2000; Higgins, 2000; Cfee e Lipscomb, 2009; Ridgway e Harrison, 1998

Gram-negative

Proteus sp., Morganella morganii, Alcaligenes sp., Citrobacter sp.,

Chryseobacterium sp., Escherichia coli, Pasteurella sp., Pseudomonas sp.,

Streptococcus sp.Bonar et al., 2007

Streptococcus iniaeBonar e Wagner, 2003; Bonar et al., 2007

RESULTS AND DISCUSSION

Bacterial pneumonia

Streptococcus iniae

“Golf ball disease”

Bonar e Wagner, 2003; Bonar et al., 2007

Abscedative dermatitis and panniculitis

Pyogenic septicemia

Suppurative bronchopneumoniaSong et al., 2017

RESULTS AND DISCUSSION

Bacterial pneumonia

Streptococcus iniae

Zoonotic importance in Mid-Solimões river

Freitas e Rivas, 2006

RESULTS AND DISCUSSION

Meconium Aspiration SyndromeCase 25

Sotalia fluviatilis NeonateMarked and diffusepulmonary atelectasia Abundant aspirated material Keratinized stratified epithelium with retained nuclei (pulmonary vernix caseosa) Brown granular aggregates (meconium) 200µm

RESULTS AND DISCUSSION

Meconium Aspiration Syndrome

Sotalia fluviatilis neonate

Histopathological features described in humans and animals Van-Elk et al., 2007; Raju et al., 2010; Tanaka et al., 2014

RESULTS AND DISCUSSION

Aspiration of meconium-stained amniotic fluid in

the airways

Intrauterine gasping or during the first few breaths

Miller, 1977; Srinivasan e Vidyasagar, 1999

Indicator of fetal distress

Fetal anoxia or hypoxia

Ojha et al., 2006; Alonso-Spilbury et al., 2005; Tayade, 2012

Meconium Aspiration Syndrome

CONCLUSION

High occurrence of pulmonary pathology in free-ranging I. geoffrensis

and S. fluviatilis in the Mid-Solimões

Verminous pneumonia Bacterial pneumonia

First report of Halocercus brasiliensis infection in I. geoffrensis

First report of Meconium Aspiration Syndrome in S. fluviatilis

Understanding the impact of lung disease in these riverine speciesFuture medical and conservation efforts on these Amazonian dolphins